Updated October 2012 Calculation Progression for Addition, Subtraction, Multiplication and Division This is Hillside’s Calculation Policy. These documents show the methods taught throughout the school and the progression of the four operations. Please use the weekly Home Learning or Maths Facts to gauge which stage your child is at or ask your child’s class teacher. It is important that we work together to use the same calculation methods in order that we don’t confuse the children. By the end of Year 6, children will have a range of calculation methods. Selection will depend upon the numbers involved. Children should not be made to go onto the next stage if: o they are not ready o they are not confident Children should be encouraged to approximate their answers before calculating Children should be encouraged to consider if a mental calculation would be appropriate before using written methods. These notes show the stages in building up to a compact, efficient method for addition. Our aim is that children use mental methods when appropriate but for calculations that they cannot do in their heads they choose an appropriate written method which they can use accurately and with confidence. Time must be taken to build up to the most efficient method to ensure complete understanding at each stage. Counting on from a number to find the total Adding groups together (objects or pictures of objects). Use moveable objects when finding totals. Touch and align each object as it is counted. Use fingers for calculations to 10. Count first group, start count from first groups total when counting second group. Counting on from the biggest number Number Bonds to 10 and 20 Adding two groups together to find the total. Counting on in ones on a number line/hundred square Biggest number in head and counting on Jane had 3 bears. She was given 5 more. How many does she have now? To support learning of number facts using a variety of visual resources Addition by adding on in multiples of tens (by jumping down) and ones (by jumping along) on a hundred square. Number bonds to 10, 20 and pairs of multiples of tens to 100. Addition by partitioning one number on an empty number line 23 + 12 = 35 10 +2 +10 +2 ___________________ 23 33 35 Continued on next page 2 Addition as partitioning and recombining 42 + 36 40 + 2 + 30 + 6 70 + 8 = 78 Addition by partitioning one number on an empty number line 34 + 35 = +10 +10 +10 +5 __________________________________ 34 44 54 64 69 Addition with chunking 34 + 35 = +30 +5 ____________________________________ 34 64 69 Number bonds to 100 Addition by partitioning one number on an empty number line: 124 + 145 = 124 + 100 +40 + 5 +100 124 +40 224 +5 264 269 Addition as partitioning and recombining: 133 + 158= 100 + 30 + 3 + 100 + 50 +8 200 + 80 + 11 = 291 Continued on next page 3 Stage 1 of column method: Adding tens first then units up to 1000 (building on mental calculation strategies that add biggest numbers first) 43 +54 90 7 97 Stage 2 of column method: Expanded Addition Adding units first, then 10’s, then 100’s 358 + 33 11 80 300 391 Stage 3 of column method: Compact Method Adding units first then 10’s then 100’s 358 + 33 391 1 Stage 3 of column method: Compact method/formal written method Extend to addition of 4 digit numbers 3587 + 675 4262 11 1 Extend to addition of more than 2 numbers 671 98 468 1237 21 Continued on next page 4 Extend to 1 place decimals 72. 5 +54. 6 127. 1 1 Extend to 2 place decimals £ 73.42 +£ 84.73 £158.15 1 Continue with compact method 3481.9 26.85 + 0.71 3509.46 1 2 Addition with time on the number line method +1 hour +17mins _______________________________________ 9:23 10:23 10:40 5 These notes show the stages in building up to a compact, efficient method for subtraction. Our aim is that children use mental methods when appropriate but for calculations that they cannot do in their heads they choose an appropriate written method which they can use accurately and with confidence. Time must be taken to build up to the most efficient method to ensure complete understanding at each stage. To use practical apparatus to take away objects Using fingers to subtract Subtraction stories to ten using pictures Subtraction as counting back on a number line/hundred square in ones Subtraction facts Finding the difference between two numbers e.g. 5 and 8 Subtraction as counting back in tens and ones on a number line and a hundred square. Subtraction as taking away on an empty number line 18-12= -10 -2 _____________________________ 6 8 18 Subtraction by partitioning 56 – 23 = 56 -20 = 36 – 3 = 33 Subtraction as taking away on an empty number line 163 -47 =116 Count back 47 from 163 -7 -10 -10 -10 -10 _______________________________________ 116 123 133 143 153 163 Continued on next page 6 Working towards taking away 40 (4 x 10) to be more efficient -7 -40 _______________________________________ 116 123 163 Subtraction as finding the difference 113 – 87 =26 -3 -10 -10 -3 ___________________________________ 0 87 90 100 110 113 Finding the difference (counting up from the smaller number strategy) 754 – 586 = 168 754 -586 4 10 100 50 4 168 (To make 590) (To make 600) (To make 700) (To make 750) (To make 754) Finding the difference (counting up method) £ 14. 24 -£ 8. 70 .30 (to make £ 9.00) £5.00 (to make £14.00) £0.24 (to make £14.24) £ 5.54 Leading to compact/formal written method £ 14. 24 -£ 8. 70 .30 (to make £ 9.00) £5.24 (to make £14.24) £5.54 Continued on next page 7 Partitioned compact method 754 -522 2 (4 – 2) 30 (50 – 20) 200 (700 – 500) 232 Leading to compact decomposition / exchanging 5 13 1 6476 -2684 3792 “If the Bigger number is on the Bottom we Exchange” We do not use the term ‘Borrow’ 4 19 19 1 5001 - 567 4434 Extend to decimal numbers 3 91 £ 4.00 -£ 2.65 £1.35 Extend to mixed decimal places 3.6 – 2.04 51 3.60 - 2.04 1.56 8 These notes show the stages in the build-up to a compact, efficient method for multiplication. Our aim is that children use mental methods when appropriate but for calculations that they cannot do in their heads they choose an appropriate written method which they can use accurately and with confidence. Time must be taken to build up to the most efficient method to ensure complete understanding at each stage. Counting in twos Number rhymes in twos such as 2, 4, 6, 8 Hopping in twos Counting on or back in 2, 5 and 10 Grouping in 2s, 5s and 10s Counting in 2s, 5s and 10s Use 100 square to see number patterns Grouping objects Understand multiplication as repeated addition 2x3=6 or 3 + 3 = 6 Understand multiplication as repeated addition: With pictures ____ + + + _____ + _____ = ______ Understand multiplication as groups 2x3=6 Continued on next page 9 5 x 5 = 5 + 5 + 5 + 5 + 5 = 20 +5 +5 +5 +5 +5 ____________________ 0 5 10 15 20 25 Must know 2, 5 10 multiplication facts: Understand multiplication as Arrays 7x5= 7 x 5 = 35 5 x 7 = 35 Should know all multiplication facts 1-10 Grid Method – TU x U 23 x 8 x 20 8 160 3 24 160 + 24 184 Begin to mentally know multiples of 10s e.g. 30 x 7 = 210 10 Grid Method – HTU x U 253 x 6 = x 6 200 1200 50 300 3 18 1200 300 + 18 1518 Grid method – TU x TU 24 x 35 = x 30 5 20 600 100 4 120 20 600 100 120 + 20 840 Grid method – ThHTU x U 4732 x 5 = x 5 4000 700 20000 3500 30 150 2 10 20000 3500 150 + 10 23660 Grid method – HTU x TU 156 x 43 = x 40 3 100 50 4000 2000 300 150 6 240 18 4000 2000 240 300 150 + 18 6708 11 Standard written method Short multiplication – TU x U 34 x 6 = 2 34 x 6 204 Leading to HTU x U 836 x 4 = 12 836 x 4 3344 Short multiplication – U.t x U 8.6 x 8 = 4 8.6 x 8__ 68.8 Leading to TU.t x U 56.9 x 7 = 46 56.9 x 7__ 398.3 Long multiplication – TU x TU 36 x 47 = 3 36 x 47 252 1440 1692 2 12 These notes show the stages in the building up to a compact, efficient method for division. Our aim is that children use mental methods when appropriate but for calculations that they cannot do in their heads they choose an appropriate written method which they can use accurately and with confidence. Time must be taken to build up to the most efficient method to ensure complete understanding at each stage. Counting in two’s Number rhymes in two’s such as 2, 4, 6, 8 Hopping in twos on a number line Counting on or back in 2, 5 and 10 on a hundred square and fingers Grouping in 2’s, 5’s and 10’s Sharing objects between groups Repeated subtraction on a number line / hundred square Use grouping of objects Sharing objects between groups 8 shared between 2 xx xx xx xx Answer = 4 8 objects grouped into 4 groups xxxx xxxx Answer = 2 As grouping by repeated subtraction using a number line: Examples without the remainder 12 -3 -3 -3 -3 = -3 -3 12÷3 = 4 -3 -3 __________________________________ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Division as repeated subtraction 72 ÷ 5 -50 (10x5) -20 (4x5) _______________________________ 0 2 22 72 72 -50 (10 x 5) 22 -20 (4 x 5) Remainder 2 Answer = 14 r2 Chunking with TU ÷ U 56 ÷ 3 = ___ )56 -30 (10 x 3) 26 -15 (5 x 3) 11 - 9 (3 x 3) 2 Answer = 18 r2 Check = (18 x 3) + 2 = 56 Leading on to Chunking with HTU ÷ U 256 ÷ 7 = ____ )256 - 70 (10 x 7) 186 - 140 (20 x 7) 46 - 42 (6 x 7) 4 Answer = 36 r 4 Check = (36 x 7) + 4 = 256 14 Short division 284÷ 6 4 7 r2 6 )2 844 Remainder as a fraction 47 r2 is the same as 47 2 6 or 47 1 3 Remainders as Decimals 47 r2 is the same as 47.33 Long Division 284 ÷ 15 1 8 r14 15 )2 8 4 -15 134 -120 14 8362 ÷ 24 3 4 8 r10 24)8 3 6 2 -7 2 116 - 96 202 - 192 010 15