CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE Workbook answers 1 Numbers to 100 Exercise 1.1 Challenge Focus 10 See the grey numbers in the grid. The black numbers refer to question 11. 1 23 = 20 + 3 49 = 40 + 9 2 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 24 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 3 37 3, 13, 23, 33, 43, 53, 63, 73, 83, 93 42 6, 16, 26, 36, 46, 56, 66, 76, 86, 96 24, 38 5 Learner’s own answers. 46 48 53 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 4 28 69 75 81 82 84 90 Practice 6 98 = 90 + 8 73 = 70 + 3 11 Learners have added 24, 28, 42, 48, 82 and 84 to the 100 square. See the black numbers in the grid in the answer for question 10. 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 Exercise 1.2 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 Focus 4, 14, 24, 34, 44, 54, 64, 74, 84, 94 1 85 = 80 + 5 7 8 9 1 ten → 10 8, 18, 28, 38, 48, 58, 68, 78, 88, 98 2 tens → 20 Learner’s own representations of 23 as 2 tens and 3 ones, and 32 as 3 tens and 2 ones. 3 tens → 30 4 tens → 40 5 tens → 50 6 tens → 60 7 tens → 70 8 tens → 80 9 tens → 90 10 tens → 100 27 23 33 57 58 59 43 44 67 47 74 77 78 84 87 87 88 89 94 95 96 97 1 36 37 38 98 2 90 (or 9 tens) 3 50 (or 5 tens) 4 a 75: 70, 5 c 40: 40, 0 b 39: 30, 9 Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 5 Estimate 50 or 100. Count 53. 6 24, 36, 42, 78, 12 10 Learner ticks 1st leaf, underlines 4th leaf and rings 8th leaf. Practice 11 Start/Begin at 78. Count back in twos. Stop at 70. 7 100, 90, 80, 70, 60, 50, 40, 30, 20, 10 12 36 is smaller than 63. 8 Marcus 5 and 8, Arun 3 and 7. 13 19, 46, 57, 64, 75 9 Estimate 50 or 100. Count 67. Challenge 10 An even number of objects can be sorted into 2 equal groups. 2 more than an odd number is always an odd number. Challenge 11 Large dots: estimate 20 or 50; count 21. Small dots: estimate 50 or 100; count 48. 12 For example, an L shape. Learners may have other ideas. 16 Learner’s own answer and matching description. 17 84, 82, 48, 42, 28 2 Geometry Focus Focus Learner will have marked the number line with 15 halfway between 10 and 20, 43 approximately a quarter of the way between 40 and 50 and 78 approximately three-quarters of the way between 70 and 80. 15 15 52nd and 53rd Exercise 2.1 Exercise 1.3 1 14 54 and 87. Accept 53, 86 or 88. 43 1 b Box: cuboid, 6 faces, 12 edges, 8 vertices, 0 curved surfaces. 0 10 20 30 40 50 60 70 80 90 100 Learner will have ringed the 3rd elephant. 3 32nd 4 42, 52, 62, 72 5 32, 34, 36, 38 6 even, ones 7 53 is greater than 35. 8 12, 21, 35, 53 Practice 9 Ball: sphere, 0 faces, 0 edges, 0 vertices, 1 curved surface. Tin can: cylinder, 2 faces, 2 edges, 0 vertices, 1 curved surface. 78 2 aThis shape is a cube. It has 6 faces. It has 12 edges. It has 8 vertices. Square-based pyramid: 5 faces, 8 edges, 5 vertices, 0 curved surfaces. 2 cuboid, sphere, cylinder, cube, square-based pyramid 3 Any 2D shape that is flat and cannot be picked up: for example, shapes in pictures, on wallpaper, on an item of clothing, on a floor or wall tile. Any 3D shape that can be picked up and can include a can of beans, a cereal box, a cupboard, a ball, a box. Learner marks 3 about a quarter of the way between 0 and 10 and 49 just before 50. 3 49 0 10 20 30 40 50 60 70 80 90 100 2 Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 4 Shape Faces Edges Curved surfaces Sphere 0 0 1 0 Cylinder 2 2 1 0 Squarebased pyramid 5 8 0 5 Cube 6 12 0 8 Cuboid 6 12 0 8 Shapes Vertices What is the same? What is different? Square- Both have based vertices pyramid and at least 1 square Cube face. The square-based pyramid has 1 square face and 5 vertices. Practice 11 Outside the circle: sphere, cylinder. Inside the circle: cube, pyramid, cuboid. 5 The shape could be a cube, cuboid or squarebased pyramid. 12 6 aA sphere, B cylinder, C square-based pyramid, D cube, E cuboid b square-based pyramid c cube 7 Inside the circle is a sphere and a cylinder. The other 3D shapes are outside the circle. 8 3D shapes can include a can of beans, a cereal box, a cupboard, a ball, a box. 3D shape The 2D shapes will be the faces of the 3D shapes. For example, a can of beans has 2 circular faces; a cereal box has 6 rectangular faces. Challenge 9 Max is wrong because a square-based pyramid has 8 edges. 10 Shapes Cube Cuboid What is the same? What is different? Both have 6 faces, 12 edges and 8 vertices. The cube has square faces. 2D shape This cuboid has 2 square faces and 4 rectangle faces. Cylinder Both have The cylinder has Sphere a curved 2 circular faces; the surface and sphere does not. no vertices. 3 The cube has 6 square faces and 8 vertices. Name Picture 2D shapes I can see Sphere Circle Cube 6 squares Cuboid 2 squares and 4 rectangles Squarebased pyramid 4 triangles and 1 square Name Picture 3D shapes I can make Circle Sphere, cylinder Square Cube, cuboid Rectangle Cuboid Triangle Trianglebased pyramid Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE Exercise 2.2 4 Focus 1 Learner draws lines of symmetry on each shape. 2 Rectangle, hexagon, octagon, pentagon. Learner’s own answers for shape descriptions. For example, a rectangle has 4 sides and 4 vertices. A hexagon has 6 sides and 6 vertices. Challenge 5 Learner draws as many lines of symmetry on each shape as they can see. E.g.: Practice 3 4 Ladybird, star, rocket and tree are all symmetrical. The ladybird and tree have vertical lines of symmetry. The rocket has a horizontal line of symmetry. The star has a vertical and a horizontal line of symmetry. Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 3 The learner colours in a quarter of each of the items. Learner’s own drawings of things you can cut in quarters with one quarter of each coloured. 4 Learner’s own answer. Practice 6 Learner’s completed face should also be coloured symmetrically. 5 Exercise 2.3 Focus 1 2 Half of each of the fruits are coloured in by the learner. Learner’s own drawings of things you can cut in half with one half of each coloured. Half: 6 coloured squares Whole: 12 coloured squares 1 1 + = 1 whole 2 2 5 6 The circle, cross and diamond show quarters and learners will colour one quarter of those. 7 Each shape should have a different quarter coloured. Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE Challenge 8 5 whole biscuits 9 a 1 4 c 1 2 10 9 centimetres; 5 centimetres; 11 centimetres; 4 centimetres; 13 centimetres b three-quarters 11 a30 centimetres, 39 centimetres, 50 centimetres, 70 centimetres 10 Learner’s own answers. The answer should always be 2 squares as a quarter of 8 is 2. 77 centimetres, 78 centimetres, 87 centimetres, 88 centimetres c 1 metre, 1 metre, 3 metres, 4 metres 2 11 a 1 4 b three-quarters 12 Learner’s own answers. c 1 2 d 1 2 Exercise 3.2 3 Measures Focus 1 Exercise 3.1 a 8 centimetres b 2 centimetres c 13 centimetres d 7 centimetres e 11 centimetres Focus 2 1 The answers will be different if the length of each object is different. Practice 2 Learner’s own answer. 3 For example: Longer: a frying pan; a table; a skipping rope. 4 Learner’s own answers. 3 a, b Answers depend on the location. 4 Learner’s own answers. 5 Shorter: a straw; your shoe; your hand; a fork. aA pencil case centimetres; a bus metres; a pencil centimetres; a wall metres; a book centimetres; a car metres. About the same: a paint brush. b But these depend on the learners. Learner’s own answer. Learner’s own answers. Challenge 6 A is longer. It is 3 centimetres longer than B. Practice 7 A is shorter. It is 3 centimetres shorter than B. 5 8 B is shorter. It is 3 centimetres shorter than A. 9 A is longer. It is 14 centimetres long. The shorter line is 13 centimetres long. The longer line is 1 centimetre longer. 6 7 Answers will depend on the length/height of the learner. The answers are different because each object is a different length. They are nonstandard measures. The pen is 9 centimetres long. Learner’s own answers for objects that are longer and shorter than the pen. Metres: swimming pool; bus. 8 Learner’s own answer. Challenge 9 Learner’s own answer. 10 a 7 centimetres c 7 centimetres 11 a Centimetres: bar of chocolate; shoe; 5 paper clips joined together; worm. 6 b b 6 centimetres apple 10 centimetres b strawberry about 5 centimetres c pencil 20 centimetres d tree 5 metres e plaster 5 centimetres Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 7 4 Statistics Focus Not 2 or fewer legs Learners should have completed the table with the results from their 12 spins. It is unlikely that they will have landed on each number twice, so their experiment should have shown that Arun is not correct. 2 Triangle Not triangle Striped 5 Working with numbers to 100 Exercise 5.1 Focus Not striped 1 7, 6 2 Learner’s own arrangements of 5 counters. 3 a 25 + 4 = 29 b 42 + 5 = 47 c 51 + 7 = 58 d 33 + 6 = 39 a 28 + 10 = 38 b 32 + 10 = 42 12 c 54 +20 = 74 d 41 + 20 = 61 9 5 35 + 20 5 55 b 6 + 5 + 4 = 15 6 + 4 = 10 10 + 5 = 15 b 31 + 8 = 39 Practice 3 Starfish tally chart Starfish Tally Number 6 14 4 6 4 a 5 + 5 + 5 = 15 5 + 5 = 10 10 + 5 = 15 c 8 + 4 + 2 = 14 8 + 2 = 10 10 + 4 = 14 17 4 4th week 29 bikes. 1st week 16 bikes. 2nd and 3rd weeks 42 bikes. Practice 7 87 bikes altogether. 5 2D shape Not a 2D shape Spots 8 No spots 9 Challenge 6 7 Cannot fly 2 or fewer legs Exercise 4.1 1 Can fly a 64 + 5 = 69 c 84 + 3 d 92 + 6 87 98 a b 89 + 10 = 99 26 + 20 = 46 c 68 + 20 d 77 + 10 88 87 18 + 2 = 20 8 + 12 = 20 80 + 20 = 100 Answer depends on the learner’s spins. Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE Exercise 5.2 10 0 + 6 = 6 0 + 60 = 60 1+5=6 10 + 50 = 60 Focus 2+4=6 20 + 40 = 60 1 3+3=6 30 + 30 = 60 39 − 8 = 31 b 48 − 5 = 43 c 77 − 5 = 72 d 59 − 7 = 52 a 24 − 10 = 14 b 41 − 10 = 31 c 52 − 20 = 32 d 38 − 20 = 18 22 + 6 = 28 b 37 – 5 = 32 11 a 3 + 6 + 7 = 16 b 3 + 7 = 10 10 + 6 = 16 0 + 7 + 10 = 17 0 + 10 = 10 10 + 7 = 17 2 c 1 + 5 + 8 = 14 d 1 + 1 + 8 = 10 10 + 4 = 14 2 + 9 + 5 = 16 1 + 9 = 10 1 + 10 + 5 = 16 3 a 4 27 − 3 = 24 14 + 10 = 24 34 − 10 = 24 29 − 4 = 25 29 – 4 = 25 has a different answer to the others. Challenge 12 a 58 + 20 b 62 + 7 c 46 + 20 78 69 66 d 83 + 6 e 55 + 30 f 71 + 8 89 85 79 Practice 5 13 4 + 16 = 20 or 14 + 6 = 20. Accept the same but reordered number sentences. 14 0 + 90 = 90, 10 + 80 = 90, 20 + 70 = 90, 30 + 60 = 90, 40 + 50 = 90. 6 15 Answers depend on how learners choose to add the numbers unless there is a known complement to 10. Possible solutions include: 7 + 3 + 8 = 18 7 + 3 = 10 10 + 8 = 18 6 + 8 + 5 + 2 = 21 8 + 2 = 10 10 + 6 + 5 = 21 2 + 3 + 4 + 5 = 14 5 + 2 + 3 = 10 10 + 4 = 14 3 + 4 + 7 + 8 = 22 10 + 4 + 8 = 22 10 + 10 + 2 = 22 5 + 6 + 7 + 8 = 26 11 + 7 + 8 = 26 11 + 10 + 5 = 26 1 + 4 + 5 + 8 + 9 = 27 10 + 4 + 5 + 8 = 27 10 + 10 + 2 + 5 = 27 16 Example: a 57 − 4 = 53 b 88 − 3 = 85 c 69 − 5 = 64 d 48 − 5 e 89 − 8 f 77 − 7 43 81 70 e 89 f 45 − 30 − 20 59 25 a 57 −10 = 47 b 94 − 20 = 74 c 66 − 30 = 36 d 78 − 10 68 7 a 8 32 + 5 ✓ b 42 − 20 = 22 35 + 30 = 65 45 − 20 52 + 40 99 − 8 25 92 91 9 52 8 3 4 1 5 9 10 a 6 7 2 11 68 + 30 83 − 3 79 − 7 66 − 60 98 80 72 6 If learners struggle, suggest that putting 5 in the middle square might help. A further hint could be to think about complements of 10, because 10 + 5 = 15. 8 a Challenge 68 − 5 = 63 b 32 + 30 = 62 12 41 Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE Exercise 5.3 13 45, 60, 18 Focus 14 Pyramid 1 (5, 1, 2) middle row 5, 2; top row 10. Pyramid 2 (2, 2, 5) middle row 4, 10; top row 40. Pyramid 3 (2, 1, 10) middle row 2, 10; top row 20. 1 10 + 10 + 10 + 10 + 10 = 50 and/or 10 × 5 = 50 2 5 + 5 + 5 + 5 = 20 and/or 5 × 4 = 20 3 2 + 2 + 2 + 2 = 8, 2 × 4 = 8 4 10 × 3 = 30 5 Learner’s own answer. 6 2×1=2 2×4=8 2 × 7 = 14 2 × 10 = 20 Exercise 5.4 Focus 2 × 8 = 16 1 2×2=4 2 × 5 = 10 2 × 8 = 16 2×3=6 2 × 6 = 12 2 × 9 = 18 Practice 7 8 9 5 + 5 + 5 + 5 + 5 = 25, 5 × 5 = 25 b 4 jumps of 2 from 8 to 0 on the number line, 8 ÷ 2 = 4. 2 a 20 ÷ 10 = 2 3 15 ÷ 5 = 3 and/or 15 ÷ 3 = 5 4 20 ÷ 5 = 4 Multiplication 10 = 10 10 × 1 = 10 10 + 10 + 10 = 30 10 × 3 = 30 5+5+5+5+5+5+ 5 + 5 = 40 5 × 8 = 40 5 + 5 + 5 + 5 + 5 + 5 = 30 5 × 6 = 30 6 45 ÷ 5 = 9 2 + 2 + 2 + 2 + 2 + 2 = 12 2 × 6 = 12 7 Learner’s own answers. 2+2=4 2×2=4 Learner’s own arrays, with 2 columns of 9 and 6 columns of 5, or 9 columns of 2 and 5 columns of 6. Double Addition 5 b 8 9 jumps of 10 on the number line from 90 to 0, 90 ÷ 10 = 9. a 12 ÷ 2 = 6 c 70 ÷ 10 = 7 a multiply 2 × 3 = 6 b divide 18 ÷ 2 = 9 Challenge Double 10 is 20 10 + 10 = 20 10 × 2 = 20 Double 1 is 2 1+1=2 1×2=2 9 Double 2 is 4 2+2=4 2×2=4 Challenge 12 × 1 2 5 10 1 1 2 5 10 2 2 4 10 20 5 5 10 25 50 10 10 20 50 100 20 ÷ 2 = 10 a10 jumps of 5 on the number line from 50 to 0, 50 ÷ 5 = 10. Multiplication 11 6, 5, 40 b Practice Repeated addition 10 9 a4 jumps of 5 from 20 to 0 on the number line, 20 ÷ 5 = 4. 30 ÷ 5 = 6 b 40 ÷ 5 = 8 30 ÷ 6 = 5 10 a divide 100 ÷ 10 = 10 b multiply 2 × 9 = 18 11 Learner’s own answer. For example, there are 60 cherries and 10 children. How many cherries does each child get? Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 6 Money 7 Time Exercise 6.1 Exercise 7.1 Focus Focus 1 100 1 2 Even value: missing US$2 banknote. Not even value: missing US$5 banknote. For example, lunch time, TV programme, film, football match. 2 second, minute, hour, month, year 3 7, 12 4 2nd, 29th, 21st, 5th 5 a Friday 12th November 2021 b Sunday 5th December 2021 c Tuesday 30th November 2021 a 13/07/20 c 23/02/22 3 4 5 Any combination of coins which makes 25c, for example, 1 quarter dollar (25c), or 2 dimes (10c) and 1 nickel (5c), or 5 nickels (5c). Any combination of banknotes which makes US$30, for example, US$20 and US$10, or 3 US$10 or 6 US$5. Any combination of banknotes and coins which makes US$5 and 45c, for example, US$5, 4 dimes and a nickel or 2 US$2, US$1, a quarter dollar and 2 dimes. Practice 10 6 7 b 11/09/21 Answers will depend on current date. Practice 6 35c 7 Banknotes and coins with one or 1 on (or similar wording). 8 Any combination of banknotes which makes US$62 and 15c, for example, US$50, US$10, US$2 and 3 nickels or 3 US$20, US$2, 1 dime and 1 nickel. 8 For example, sing a song, sneeze, watch a film. In order of shortest to longest: sneeze, sing a song, watch a film. 9 a 1st b 31st c 21st d 30th 10 Saturday 14th May 2022 14/05/22 Challenge Tuesday 17th May 2022 17/05/22 9 Thursday 9th June 2022 09/06/22 Wednesday 22nd June 2022 22/06/22 US$5 and 5c coin, US$1 coin and 1 dime coin. 10 For example, 70c: Marcus half dollar and 2 dimes; Sofia 2 quarter dollars, 1 dime and 2 nickels. 85c: Marcus half dollar, quarter dollar, dime; Sofia half dollar, 3 dimes and 1 nickel. 11 a 11 Challenge Country or region Lower value unit Higher value unit Your country Own lower value unit, if relevant Own higher value unit, if relevant USA c $ European Union c € Japan none ¥ UK p £ c July b September February d November 12 year, month, week, weekend, day, hour, minute, second 13 September and December; May; August. Sunday 1st January 2023 Friday 31st December 2021 14 Friday 29th May 15 Saturday 14th August Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 8 Numbers to 100 (2) Exercise 8.2 Exercise 8.1 1 Focus a 1 b 2 c 3 d 4 e 5 f 7 2 a 16 ÷ 2 = 8 3 a 1 b 2 c 3 d 5 e 5 f 2 a 16 ÷ 4 = 4 Focus 1 2 3 a fifty-three b seventy-one c twenty-nine d forty-seven a 86 b 34 c 47 d 62 a 10s 1s 10s b 1s 4 1 of 16 = 8 2 b 1 of 16 = 4 4 b Practice 4 5 a 50 b 70 c 50 d 40 e 30 f 90 For example, 20 + 4, 10 + 14, 11 + 13, 12 + 12, 10 + 10 + 4, 10 + 10 + 3 + 1. Practice 6 fifty-one, fifty-four, fifty-five, sixty-one, sixty-four, sixty-five, ninety-one, ninety-four, ninety-five; 9 numbers. 7 54 8 Zara needs to look at the ones to round to the nearest 10. 5 ones would round up to the next 10, but 50 is 5 tens and 0 ones. It is already a tens number so does not need to be rounded. 9 For example, 20 + 10 + 5, 21 + 12 + 2, 21 + 13 + 1, 20 + 11 + 4. Challenge 1 2 6 It is the denominator. It represents how many equal parts the whole has been split into. 7 Learner should draw 5 marbles. 8 2 9 20 10 1 + 1 + 1 = three-quarters (or 3 ) or 4 4 4 4 1 1 1 1 1 + = , + = three-quarters. 4 4 2 2 4 11 1 + 1 + 1 + 1 = 4 = 1 4 4 4 4 4 Challenge 12 3, 8 13 2 of 12 and 12 ÷ 2 = 6 ticked. 4 14 Marcus used 1 . Zara used 1 . 10 a sixty-two b seventy-one c fifty-nine d forty-seven 2 thirty-seven add twenty equals fifty-seven 15 a b ninety-nine subtract (or take away) seven equals ninety-two b 13 30 metres, 50 metres 14 The other two numbers must total 26, for example, 20 + 6, 16 + 10, 13 + 13, 12 + 14, 11 + 15. 4 Arun and Zara used 1 + 1 = 1 . 4 4 2 11 a 12 60 centimetres, 90 centimetres 11 5 1 2 8 pieces. Yes, all pieces are 1 , so any 4 8 pieces will make 2 whole sandwiches. 16 Swap the dollar for 4 quarters (quarter dollar) coins and give 1 to your friend. 25 c 25 c 25 c 25 c Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 9 Statistics (2) Exercise 9.2 Exercise 9.1 1 Chocolate was the most popular. Coffee was the least popular. 16 ice creams were eaten. 2 Team B has scored most goals. Team E has scored the least goals. 1 more goal was scored by Team B than Team D. Team E scored 2 goals fewer than Team A. Focus Focus Numbers Odd 9 2 3 More than 20 25 13 21 62 78 Flies, walks. But learners may decide on different labels. Practice 3 5 like orange juice. 2 like water. Cola was liked by 3 children. 2 more children preferred milk to tea. 16 children were asked altogether. Learner’s own answer. 4 Ara’s family name has 6 letters. Ohan’s family name has 7 letters. Akila’s family name has 8 letters. Learner’s own answers. Practice 4 Akila’s family name has most letters. Kai’s family name has least letters. Red: apple, strawberry, cherries, pepper, tomatoes. Ohan’s family name has 3 more letters than Kai’s family name. Green: apple, lime, avocado, kiwi fruit, broccoli. Ara’s family name has 2 fewer letters than Akila’s family name. Red and green in the overlap: apple, mango. 5 6 12 5 23 6 Learner’s own answer. Learner’s own questions. Challenge Challenge 7 29 pieces of fruit in the bowl. 1 more pear. 1 fewer banana. Most fruit is apples. Least fruit is mango. 6 Use of digits in 5 telephone numbers Cats in the cat shelter Grey Large Poppy Tilly 12 5 Magic Scrumpy 8 Learner’s own answer. 9 41, 84, 59, 16, 25, 75 Jack Monty Number of times used 1 0 Milk 41 Sugar 84 Sugar but not milk 59 Milk but not sugar 16 Milk and sugar 25 Milk or sugar 75 1 2 3 4 5 6 7 8 9 Learner’s own questions. Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 10 Calculating 6 Exercise 10.1 Focus 1 53 31 63 71 23 61 32 63 + 25 = 53 + 35 and 37 − 12 = 39 − 14 ticked, possible corrections include 53 + 24 = 54 + 23 and 85 − 33 = 95 − 43. = 30 + 2 + 20 + 6 8 51 and 97. = 30 + 20 + 2 + 6 Challenge = 50 + 8 9 32 + 26 = 58 b 21 7 Accept reordering of the numbers. a 42 10 41 + 35 Smallest total 13 + 24 = 37 or 14 + 23 = 37. Greatest total 52 + 43 = 95 or 53 + 42 = 95. 1 = 40 + 1 + 30 + 5 7 2 5 = 40 + 30 + 1 + 5 = 70 + 6 7 = 76 c 3 5 3 6 8 6 5 4 9 4 7 1 9 8 23 + 34 10 = 20 + 3 + 30 + 4 6 11 12 3 7 13 4 = 20 + 30 + 3 + 4 14 = 50 + 7 2 4 1 = 57 2 d 57 + 21 e 43 + 14 f 23 + 24 Exercise 10.2 78 57 47 Focus 1 Calculation Inverse 7 + 3 = 10 10 − 3 = 7 13 + 5 = 18 18 − 5 = 13 32 + 17 = 49 49 − 17 = 32 8−6=2 2+6=8 46 − 12 19 − 12 = 7 7 + 12 = 19 = 40 − 10 + 6 − 2 28 − 15 = 13 13 + 15 = 28 38 − 25 = 30 − 20 + 8 − 5 = 10 + 3 = 13 = 30 + 4 = 34 3 a 4 34 − 21 = 13, 67 − 46 = 21 27 + 12 = 39 Practice 5 13 b 33 + 24 = 57 2 For example, 13 + 7 = 20, 20 − 7 = 13. 3 5 + 1 = 6 6=5+1 1 + 5 = 6 6=1+5 6 − 1 = 5 5=6−1 6 − 5 = 1 1=6−5 Learner’s own answers. Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE Practice 4 5 6 7 8 a 27 − 12 b 11 + 23 15 34 c 87 − 35 d 32 + 64 52 96 a 33 + 24 b 49 − 27 57 22 c 76 − 42 d 65 + 14 34 79 13 + 7 = 20 13 + 15 = 28 20 = 13 + 7 28 = 13 + 15 7 + 13 = 20 15 + 13 =28 20 = 7 + 13 28 = 15 + 13 20 − 13 = 7 28 − 13 = 15 7 = 20 − 13 15 = 28 − 13 20 − 7 = 13 28 − 15 = 13 13 = 20 − 7 13 = 28 − 15 90 − 50 = 40 40 = 90 − 50 90 − 40 = 50 50 = 90 − 40 a54 + 35: estimate 50 + 40 = 90; 54 + 35 = 89; inverse 89 − 35 = 54. b 77 − 44: estimate 80 − 40 = 40; 77 − 44 = 33; inverse 33 + 44 = 77. 11 40 + 34 = 74, 74 − 34 = 40 41 + 33 = 74, 74 − 33 = 41 42 + 32 = 74, 74 − 32 = 42 43 + 31 = 74, 74 − 31 = 43 44 + 30 = 74, 74 − 30 = 44 Other solutions require regrouping of ones, which is beyond Stage 2 expectations. 12 69 − 42 = 27, 27 + 42 = 69 68 − 41 = 27, 27 + 41 = 68 67 − 40 = 27, 27 + 40 = 67 Other solutions require regrouping of ones, which is beyond Stage 2 expectations. Exercise 10.3 Focus 1 10 × 4 = 40, 5 × 3 = 15, 10 × 9 = 90 2 Multiplying by 2 Doubling 1×2=2 1+1=2 10 × 2 = 20 10 + 10 = 20 2×2=4 2+2=4 5 × 2 = 10 5 + 5 = 10 3 10 × 1 = 10 → 1 × 10 = 10, 2 × 5 = 10 or 5 × 2 = 10; 2 × 10 = 20 → 10 × 2 = 20, 4 × 5 = 20 or 5 × 4 = 20; 4 × 2 = 8 → 2 × 4 = 8, 1 × 8 = 8 or 8 × 1 = 8. 4 4×1=2×2 Practice 5 Challenge 9 a 53 + 45 b 47 − 33 98 14 c 86 − 61 d 42 + 53 25 95 10 The two numbers that are added together to find the complement are the same (30). There are only 2 possible subtractions. The related subtractions are 60 − 30 = 30 and 30 = 60 − 30. 14 1 × 5 = 5 and 9 × 5 = 45 2 × 5 = 10 and 8 × 5 = 40 3 × 5 = 15 and 7 × 5 = 35 4 × 5 = 20 and 6 × 5 = 30 1 × 10 = 10 and 4 × 10 = 40 2 × 10 = 20 and 3 × 10 = 30 6 7 3 × 2 10 + 10 10 × 2 6+6 1 × 2 3+3 6 × 2 1+1 1 × 5 = 5, 2 × 5 = 10 5 × 5 = 25 or 10 × 5 = 50 Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE Challenge 6 Division fact Fraction fact 18 ÷ 2 = 9 1 of 18 = 9 2 8 10, 20, 30, 40, 50. Numbers with 5 ones are not multiples of 10. 5 × 2 = 10, so only multiples of 10 are in both tables. 9 Biscuits cost a nickel each, 5c. The calculation should be 5 × 4 = 20, 20c. 14 ÷ 2 = 7 1 of 14 = 7 2 Cakes cost a dime each, 10c. The calculation 10 × 7 = 70, 70c is correct. 16 ÷ 4 = 4 1 of 16 = 4 4 4÷4=1 1 of 4 = 1 4 10 1 × 7, 2 × 6, 5 × 3, 5 × 4, 10 × 3, 10 × 5. Exercise 10.4 Challenge Focus 1 2 10 × 1 = 10 10 ÷ 10 = 1 10 × 2 = 20 20 ÷ 10 = 2 10 × 3 = 30 30 ÷ 10 = 3 10 × 4 = 40 40 ÷ 10 = 4 10 × 5 = 50 50 ÷ 10 = 5 10 × 6 = 60 60 ÷ 10 = 6 10 × 7 = 70 70 ÷ 10 = 7 10 × 8 = 80 80 ÷ 10 = 8 10 × 9 = 90 90 ÷ 10 = 9 10 × 10 = 100 100 ÷ 10 = 10 7 Zara’s: 8 cubes, 1 of 16 = 8, 16 ÷ 2 = 8. 2 Arun’s: 4 cubes, 1 of 16 = 4, 16 ÷ 4 = 4. 4 8 40 ÷ 10, 1 of 20, 1 of 12, 18 ÷ 2, 6 × 2. 9 More than 4 of the following: 4 2 1 × 8 = 2 × 4 = 8 ÷ 1 = 16 ÷ 2 = 40 ÷ 5 = 80 ÷ 10 = 1 of 16. 2 11 Geometry (2) Exercise 11.1 2×3=6 → 6÷2=3 Focus 1×5=5 → 5÷1=5 1 5 × 7 = 35 → 35 ÷ 5 = 7 3 × 5 × 2 = 10 ÷ 1 or 20 ÷ 2 or 50 ÷ 5 or 100 ÷ 10 × 9 × 1 = 9 ÷ 1 or 18 ÷ 2 or 45 ÷ 5 or 90 ÷ 10 Practice 4 5 × 4 = 20, 20 ÷ 5 = 4; 3 × 10 = 30, 30 ÷ 10 = 3. 5 Any paired multiplication and division facts that are equivalent in value. Start × × 5 turns; 2 anticlockwise turns; 3 clockwise turns. 2 15 × Learner’s own answer. Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 3 Shape Predict Check Learner’s own prediction once Learner’s own prediction once Learner’s own prediction 4 times Learner’s own prediction 6 Three half turns will give the same answer as one half turn. Challenge twice 7 Learner’s own answer. 8 a I can make two quarter turns clockwise. An equilateral triangle b Practice 4 Learner’s own answer. 5 a I can make a half turn anticlockwise. Learner’s answers can include: • one quarter turn anticlockwise • one half turn clockwise then one quarter turn clockwise • three quarter turns clockwise • one quarter turn clockwise then one half turn clockwise. 9 b c Exercise 11.2 Focus 1 The final circle shows the centre dot. Learner’s own answer. Practice 2 16 4 centimetres, 5 centimetres, 6 centimetres Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE Challenge Practice 3 5 Learner draws a further 5 lines, which would mean there would be 12 lines coming from the centre to the edge. All lines coming from the centre should be the same length. 12 Telling the time 11 12 1 10 2 9 3 8 4 7 6 5 9 3 Focus 8 4 1 4:10 10:25 8:15 6:05 2 Analogue clocks showing quarter past 6, twenty minutes past 7, five minutes past 5, twenty-five minutes past four. 11 12 1 10 2 3 4 7 6 5 6 11 12 1 10 2 9 8 7 6 5 7 4 6 5 9 3 8 4 7 3:45 4 6 5 7 6 5 11:55 9 3 8 4 7 6 5 14:35 11 12 1 10 2 10:10 9 3 8 4 7 6 5 3 Challenge 4 7 Learner’s own answer. Words and clocks matching in each column. 8 Row 1: 9 3 8 4 9 5 8 11 12 1 10 2 11 12 1 10 2 6 3 6:20 Clocks showing the correct times. Quarter past 9: 09:15, Morning. Quarter to 7: 06:45, Evening. Quarter to 4: 03:45, Afternoon. 11 12 1 10 2 7 9 11 12 1 10 2 3 8 8:25 11 12 1 10 2 Exercise 12.1 9 11 12 1 10 2 8 3 7 6 5 4 15 minutes Row 2: Row 3: ring around 10 minutes past 8. Row 4: ring around 20 minutes past 10. 17 Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 9 Quarter of an hour is 15 minutes, not 25. Half an hour is 30 minutes not 50. Some people may think that, for example, quarter past 9 is 9:25 and half past 9 is 9:50. 13 Measures (2) Exercise 13.1 Focus 1 Pear mass is 20 grams. b Scales should show 70 grams. c Scales should show 50 grams. 50 grams flour, 1 egg, 25 grams sugar. 3 Caterpillar 3 grams. Bug 1 gram. 3 pencils 15 grams. 4 Scales should show: 5 kilograms, 8 kilograms, 7 kilograms. 5 a2 frogs = 6 blocks. 1 frog = 3 blocks. Taking away 1 frog will make the scales dip on the blocks side. 1 frog is lighter than 6 blocks. 2 frogs = 8 sweets. 1 frog = 4 sweets. When taking away 3 sweets, the frogs would be lower than the sweets. 2 frogs are heavier than 5 sweets. 6 8 18 Brick ✓ Baby ✓ Cat ✓ Mouse ✓ Fly ✓ No, larger objects are not always heavier than smaller objects. Learner’s own answer. 11 If the temperature increases, the number increases/gets larger. If the temperature decreases, the number decreases/gets smaller. a 10 °C b 15 °C d 18 °C e 19 °C c 12 °C Challenge 12 Learner’s own answer. 13 a 7 kilograms b 6 kilograms c 5 kilograms d 2 kilograms Another pebble would make the pebble side lower than the side with the bird. 14 There are many answers. For example, 100g can be 50 + 50, 10 × 10, 5 lots of 20, 100 × 1, 20 lots of 5 or 50 lots of 2. 2 pebbles are heavier than 1 bird. 15 a Learners can give any pairs of temperatures that have a difference of 9. Practice 7 Less than About More than 1 kilogram 1 kilogram 1 kilogram 10 Learner’s own answer. 2 c Object Learner’s own answer for final two rows. a b 9 9 grams 54 grams 26 grams 82 grams 32 grams 100 grams 56 grams 90 grams 14 kilograms 5 grams 1 grams 26 grams 12 kilograms 10 kilograms b 40 cubes will balance 1 pineapple. 9 cubes will balance 1 pear. 16 Both thermometers show the same temperatures of 40 °C. One thermometer shows the scale going up in 5s, the other shows it going up in 10s. One thermometer shows temperatures up to 50 °C and the other will record temperatures up to 100 °C. The learners should have drawn a line on each thermometer up to the given value. Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE Exercise 13.2 Focus 1 6 millilitres 72 millilitres 100 100 a Jugs: more, less. 90 90 b Bowls: less, more. 80 80 c Drinks: less, more. 70 70 d Dishes: less, more. 60 60 2 Milk more, spoon less, bucket more, cup less, carton less. 50 50 40 40 3 1 litre. 1 litre. 5 litres. 2 30 30 4 Bucket 9 litres, squash 1 litre, fish tank 50 litres. 20 20 10 10 Practice 5 2 litres 6 Jug 1: 7 millilitres; jug 2: 80 millilitres; jug 3: 35 millilitres; jug 4: 55 millilitres Challenge 7 Yes, the teacher has enough water. There is 1 litre left in the teacher’s bottle. 8 3 litres 9 a 14 Pattern and probability Exercise 14.1 Focus 1 litre 2 1 4 b 4 c 2 1st pattern is alternate white and black. 2nd pattern is black, grey, white repeated. 10 15 millilitres 60 millilitres 2 Learner’s own answer. 100 100 3 Marble and pencil. 90 90 80 80 70 70 60 60 50 50 40 40 30 30 20 20 10 10 Practice 4 Learner’s own answer. 5 Learner’s own answer. 6 Learner’s own answer. Challenge 7 Learner’s own answer. You would see a regular pattern on fabric, wallpaper, floor tiles or in the bricks on a house. You see a random sequence where there is no regular pattern, for example in some mosaic designs. 8 19 Learner’s own answer. Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 9 Learners do not need to name the shapes, merely draw them. The sequence is a pattern of three shapes. The first shape is always a square; the last shape is always a hexagon; the centre shape changes. 5 15 Symmetry, position and movement 6 Exercise 15.1 a b 11 12 1 10 2 11 12 1 10 2 9 3 9 3 8 4 8 4 7 5 7 6 5 6 12 11 12 1 10 2 11 12 1 10 2 9 3 9 3 8 4 8 4 Focus 1 6 7 6 5 7 6 5 12 9 11 12 1 10 2 11 12 1 10 2 9 3 9 3 8 4 8 4 7 6 5 3 7 6 5 6 Challenge 7 2 a 3 a b 6 b 6 c 3 d 9 Practice 4 For example: 20 Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021 CAMBRIDGE PRIMARY MATHEMATICS 2: TEACHER’S RESOURCE 9 Learner’s own answer. 8 10 aQuarter turn clockwise; three-quarters turn anticlockwise. 21 b Quarter turn anticlockwise; three-quarters turn clockwise. c Half a turn clockwise; half a turn anticlockwise. d Full turn clockwise; full turn anticlockwise. Cambridge Primary Mathematics 2 – Moseley & Rees © Cambridge University Press 2021