. Using negative numbers Add, subtract, multiply and divide positive and negative integers Use the sign change key to input negative numbers into a calculator Why learn this? Manipulating negativ e numbers is a crucial skill for anyone working in fi nance. You can understand adding or subtracting numbers by imagining them on a number line. Level 5 2 ⴙ ⴚ5 ⴝ ⴚ3 ⫺4 ⫺3 ⫺2 ⫺1 1 ⴚ ⴚ3 ⴝ 4 0 1 2 3 4 Did you know? 5 If you add a negative number, the result is smaller. So, adding a negative number is the same as subtracting a positive number. Level 5 If you subtract a negative number, the result is bigger. So, subtracting a negative number is the same as adding a positive number. Level 5 You can use the sign change key, into your calculator. Level 5 ⴙ ⴚ or (ⴚ) , to enter negative numbers When you multiply or divide a positive number by a negative number, the answer is negative. Level 6 The earliest known written use of negative numbers is in an Indian manuscript from the seventh century CE – but, confusingly, it uses ‘ⴙ’ as a symbol to mean negative! When you multiply or divide a negative number by a positive number, the answer is negative. Level 6 When you multiply or divide a negative number by a negative number, the answer is positive. Level 6 Level 5 I can add and subtract positive integers to/from negative integers Work out a ⴚ2 ⴚ 5 b ⴚ8 ⴙ 4 c ⴚ8 ⴚ 4 d ⴚ5 ⴙ 7 e ⴚ5 ⴚ 7 f ⴚ1 ⴚ 1 g ⴚ1 ⴙ 1 h ⴚ3 ⴙ 10 ⴚ 2 I can use the sign change key to enter negative numbers into a calculator Use the sign change key on your calculator to help with these calculations. a ⴚ303 ⴙ ⴚ61 b ⴚ48 ⴚ ⴚ211 c ⴚ13 ⴛ ⴚ5 d ⴚ481.1 ⴜ 28.3 e Hannah’s bank statement shows her balance as ⴚ£585 at the end of January. In February, she makes a deposit of £1200 and withdraws £725. What is her bank balance at the end of February? I can multiply and divide a negative number by a positive number Work out ⴚ2 ⴛ 5 4 = –10 a 2 ⴛ ⴚ5 b 3 ⴛ ⴚ4 c ⴚ12 ⴜ 3 d 12 ⴜ ⴚ3 e 15 ⴜ ⴚ5 f 12 ⴛ ⴚ6 g ⴚ24 ⴜ 3 h ⴚ3 ⴛ 12 ⴜ 4 Getting things in order add divide integer multiply negative Level 5 Work out a 13 ⴚ ⴚ3 e 3 ⴙ ⴚ8 b 4 ⴙ ⴚ5 f ⴚ15 ⴙ ⴚ16 c ⴚ1 ⴙ ⴚ5 g ⴚ2 ⴚ ⴚ2 d ⴚ19 ⴚ ⴚ11 h ⴚ5 ⴙ 11 ⴚ ⴚ2 On Monday night the temperature was ⴚ2°C. By 4.30 a.m. Tuesday, the temperature had dropped by 4 degrees. At 8 a.m. Tuesday, the temperature was 1°C. a What was the temperature at 4.30 a.m.? I can add or subtract any integers Tip Use a number line to help you. b What was the temperature change between 4.30 a.m. and 8 a.m.? Work out ⴚ8 ⴜ ⴚ2 Level 6 =4 a ⴚ5 ⴛ ⴚ3 b ⴚ4 ⴛ 8 c ⴚ20 ⴜ ⴚ5 d 39 ⴜ ⴚ3 e ⴚ11 ⴛ ⴚ7 f 12 ⴜ ⴚ1 g ⴚ9 ⴜ ⴚ9 h ⴚ3 ⴛ ⴚ4 ⴜ ⴚ2 Learn this Copy and complete. a 4ⴛ ⴝ ⴚ16 b c ⴚ72 ⴜ 8 ⴝ e ⴚ19 ⴜ ⴝ ⴚ9.5 I can multiply and divide any integers ⴛ 8 ⴝ ⴚ48 d ⴚ21 ⴜ ⴝ7 f ⴚ12 ⴛ ⴝ 60 Find two different pairs of numbers that multiply to make 28 and have a difference of 3. When multiplying or dividing with two integers: • if the signs are the same, the answer is positive • if the signs are different, the answer is negative. Work out these ii by evaluating the brackets first, and ii by expanding the brackets first. I can evaluate expressions with negative numbers and bracket Do you get the same solution each time? ⴚ2 ⴛ (3 ⴙ 5) ii –2 × (3 + 5) = –2 × 8 = –16 ii –2 × (3 + 5) = –2 × 3 + –2 × 5 = –6 + –10 = –16 a ⴚ3 ⴛ (4 ⴙ 7) A b ⴚ2 ⴛ (10 ⴚ 3) c 5 ⴛ (ⴚ2 ⴙ ⴚ4) d (3 ⴚ ⴚ8) ⴛ 7 Pattern spotting Copy and continue this pattern to find the answer to 3 ⴚ ⴚ4. 3ⴚ2ⴝ1 3ⴚ1 ⴝ2 3ⴚ0ⴝ… Write out another pattern to help you work out 5 ⴙ ⴚ3. B Power play (ⴚ1)2 ⴝ ⴚ1 ⴛ ⴚ1 ⴝ 1 Work out a (ⴚ1)3 b (ⴚ1)4 c (ⴚ1)7 d (ⴚ1)10 e (ⴚ1)17 Look for a rule for the value of (ⴚ1)n, where n is any positive integer. Write down your rule. positive sign sign change key subtract 1.1 Using negative numbers 5 .2 Indices and powers Find square numbers, square roots, cube numbers and cube roots Write numbers using index notation Use the square, square root, cube and cube root keys on a calculator Understand and use the index laws for multiplication and Why learn this? division of numbers in index form Indices are used in fo rmulae to measure the amount of space in shapes. Square numb ers are used to calculate areas, and cube numbers are used to calculate volumes. Use the index laws for positive powers of letters When you multiply a number by itself, you are ‘squaring’ it. For example 42 ⴝ 4 ⴛ 4 ⴝ 16. 16 is a square number. Level 5 Finding the square root of a number is the inverse, or opposite, of squaring. ___ √16 ⴝ 4 because 42 ⴝ 16. 4 is a square root of 16. Level 5 Watch out! A positive integer has two square roots, one positive and one negative, square but by conventi __ on the the √ to rs refe sign root positive root only. 53 is ‘five cubed’ which means 5 ⴛ 5 ⴛ 5 ⴝ 125. 125 is a cube number. Level 6 The ____inverse of cubing is finding the cube root. 3 √125 is 5 because 53 ⴝ 125. 5 is the cube root of 125. Level 6 You can write repeated multiplication of numbers using index notation. 4 ⴛ 4 ⴛ 4 ⴛ 4 ⴛ 4 ⴝ 45 and 3 ⴛ 3 ⴛ 5 ⴛ 5 ⴛ 5 ⴝ 32 ⴛ 53. Level 6 There are special rules (or ‘laws’) for working with numbers written using index notation. • When multiplying, you add the powers: Joke! 2 3 2ⴙ3 5 3 ⴛ3 ⴝ3 ⴝ3. • When dividing, you subtract the powers: 58 ⴜ 54 ⴝ 58 ⴚ 4 ⴝ 54. Level 6 & Level 7 Did you know? Why are the numbers floating? Because they’re in-da-seas! Level 5 Without using a calculator, write these squares and square roots. ___ ___ a √64 b √25 c 32 d 112 e √100 f 92 g √1 h √36 i 72 j √25 ___ _ I can recall the first twelve square numbers and their square roots ____ ___ I can use the squares I know to calculate others mentally Use the squares you know to mentally calculate these. 15 = 3 × 5, so 152 = 32 × 52 = 9 × 25 = 225 152 a 142 b 162 c 202 A 16th-century writer suggested that the 4th power should be called ‘zenzizenzic’, and the 8th power should be called ‘zenzizenzizenzic’! d 212 Estimate these square roots. Use calculator to check the exact answer. __ the square root key on your__ √8 22 = 4 and 32 = 9, so √8 lies between 2 and 3 and is closer __ to 3. I can estimate the square roots of non-square numbers Estimate: √8 = 2.8. 6 __ ___ ___ ___ a √11 b √17 c √32 d √74 Getting things in order cube cubed cube number (e.g. 2 3) __ 3 cube root (e.g. √ 8 ) index (indices) Level 6 Write these numbers as squares, cubes or powers of 10. 100 = 102 because 10 × 10 = 100 a 8 b 64 c 1000 d 10 000 e 1 000 000 I can give the positive and negative square roots of a number Work out ___ a √121 b the square roots of 81 c the square roots of 4 d √49 I can use index notation to write squares, cubes and powers of 10 ____ Rewrite these using index notation. a 2ⴛ2ⴛ2ⴛ2ⴛ2ⴛ2ⴛ2ⴛ2 b 3ⴛ3ⴛ3ⴛ3 c 7ⴛ7ⴛ7ⴛ7ⴛ8ⴛ8ⴛ8 d 5ⴛ5ⴛ5ⴛ2 Work out a 43 ___ 3 c √27 b 23 I can rewrite numbers using index notation _ 3 e √1 d 103 Use the cube numbers you know to mentally calculate these. a 63 c ⴚ93 b 83 Estimate these cube roots. __ 3 a √9 ___ d (0.1)3 ____ 3 b √21 Tip 0.1 ⴝ 1 ⴜ 10 I can estimate the cube roots of non-cube numbers ____ 3 c √50 3 d √90 I can use the index laws for multiplying and dividing numbers in index form I can use a calculator to find squares, square roots, cubes and cube roots Simplify, leaving your answers in index form. a 32 ⴛ 33 b 72 ⴛ 75 c 64 ⴛ 62 d 93 ⴛ 9 e 55 ⴜ 52 f 79 ⴜ 74 g 63 ⴜ 62 h 42 ⴜ 42 Use a calculator to write these in order, smallest first. 3 ______ √12 167 182 (ⴚ5)3 ___________ ___ √182 ⴜ √16 Level 7 Simplify these, leaving your answers in index form. A a c6 ⴛ c5 b d8 ⴜ d 2 c z3 ⴛ z4 d t5 ⴛ t3 ⴛ t6 e (r 3 ⴛ r 5) ⴜ r2 f (u9 ⴜ u4) ⴛ u2 B Squared away Keith writes the numbers 1 to 16 on cards and 8 1 15 10 begins to lay them out. Two cards next to each other always add up to make a square number. 8ⴙ1ⴝ9 1 ⴙ 15 ⴝ 16 15 ⴙ 10 ⴝ 25 etc. Lay out the rest of the cards so that this rule continues. index law index notation inverse power I can recall the cubes of 1 to 5 and 10, and their roots I can use the cube numbers I know to calculate others mentally I can use the index laws for multiplying and dividing letters in index form Binary Computers often use binary strings to store and process information. A binary string uses only the digits 0 and 1, for example 0011000101. How many different binary strings are there with a one digit b two digits c three digits? List them in each case. d How many different binary strings are there with n digits? square number square root 1.2 Indices and powers 7 .3 Prime factor decomposition Find the lowest common multiple and the highest common factor Find and use the prime factor decomposition of a number Understand and use the index laws for multiplication and division of numbers in index form Use the index laws for numbers Why learn this? Just like the element s in chemistry, prime nu mbers are the building blocks that combine to make ever y other number. The lowest common multiple (LCM) of two numbers is the lowest number that is a multiple of them both. Level 5 & Level 6 The highest common factor (HCF) of two numbers is the highest number that is a factor of them both. Level 5 & Level 6 You can write any number as the product of its prime factors. For example 90 ⴝ 2 ⴛ 3 ⴛ 3 ⴛ 5 or 2 ⴛ 32 ⴛ 5. Level 6 You can use the prime factor decomposition to find the HCF and LCM of two numbers quickly. Level 6 Did you know? To multiply powers of the same number, add the indices. 3 ⴛ3 ⴝ3 ⴝ3 4 2 4ⴚ2 To divide powers of the same number, subtract the indices. 3 ⴜ 3 ⴝ 3 ⴝ 32 Level 6 & Level 7 2 2ⴙ4 4 6 Any number to the power zero is 1. For example 30 ⴝ 1, 50 ⴝ 1, 350 ⴝ 1. Level 7 Negative powers can be written as unit fractions or decimals. 1 1 1 For example 10ⴚ1 ⴝ __ ⴝ 0.1, 10ⴚ2 ⴝ ___ ⴝ 0.01, 10ⴚ3 ⴝ ____ ⴝ 0.001. Level 7 10 100 1000 The 20th-century composer Messiaen wrote a piece of music that used prime numbers to create unpredictable rhythms. Level 5 Find all the factor pairs for these numbers. a 56 b 72 c 48 I can find all the factor pairs for any whole number d 120 I can find the HCF of two numbers Find the highest common factor (HCF) of these numbers. a 30 and 42 b 27 and 45 c 18 and 66 d 96 and 144 Find the lowest common multiple (LCM) of these numbers. 7 and 9 Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56, Multiples of 9: LCM = 63 a 12 and 20 I can find the LCM of two numbers 63 , … 9, 18, 27, 36, 45, 54, 63 , … b 15 and 25 c 30 and 42 d 33 and 121 Level 6 Find the prime factor decomposition of these numbers. 180 180 Look for a pair of factors, neither 18 3 10 6 2 2 3 8 Getting things in order 5 of which is 1. Circle the factor if it is a prime number. Continue until no further factor pairs are possible. 180 = 2 × 2 × 3 × 3 × 5 or 22 × 32 × 5 a 30 b 42 c 72 d 99 factor highest common factor (HCF) I can find the prime factor decomposition of a whole number Tip Check a prime tion by multiplying the orisa fact factors back together. index (indices) index law index form Level 6 Simplify these, leaving your answers in index form. 6 a 4 ⴛ4 b 8 ⴜ8 c 6 ⴛ6 d (4 ⴛ 4 ) ⴜ 4 e 34 ⴛ 35 f 72 ⴛ 73 g 56 ⴜ 54 h 25 ⴜ 22 5 9 3 5 3 5 I can use the index laws for multiplying and dividing numbers in index form 2 Use prime factor decomposition to find the HCF of these numbers. Complete prime factor decomposition: Identify common factors, and multiply them: 42 = 2 × 3 × 7 154 = 2 × 7 × 11 HCF = 2 × 7 = 14 a 30 and 48 d 176 and 350 42 and 154 b 30 and 100 c 180 and 210 I can find the HCF of two numbers using their prime factor decompositions Use prime factor decomposition to find the LCM of these numbers. Complete prime factor decomposition: 84 = 2 × 2 × 3 × 7 308 = 2 × 2 × 7 × 11 Multiply together all the factors but only include overlaps once: 2 × 2 × 3 × 7 × 11 = 924 84 and 308 a 35 and 42 b 30 and 100 c 180 and 810 I can find the LCM of two numbers using their prime factor decompositions d 176 and 350 I can prove that any number to the power zero is 1 a Write down the value of 23. What is the value of 23 ⴜ 23? b Use an index law to simplify 23 ⴜ 23. c What is the value of 20? Level 7 Work these out, writing your answers as decimals. a 10 ⴜ 10 3 b 10 ⴜ 10 4 7 10 c 10 ⴚ2 ⴛ 10 I can understand and use negative indices d 10 ⴜ 10 ⴚ1 2 a Use an index law to simplify 22 ⴜ 23. b What is the value of 2ⴚ1? c A whole number raised to a negative power is smaller than 1. True or false? I can use the index laws to simplify multiplication and division calculations Use prime factor decomposition to simplify these. Give your answers in index form. 45 ⴛ 48 45 = 32 × 5 and 48 = 24 × 3 so 45 × 48 = 32 × 5 × 24 × 3 = 24 × 33 × 5 a 24 ⴛ 32 A b 60 ⴛ 21 c 1500 ⴜ 75 B Factor line • Calculate the HCF of 12 and 20. • Draw a pair of axes and join the points (0, 0) and (12, 20) with a straight line. How many points with whole-number coordinates (not including (0, 0)) does the line pass through? What do you notice? • Make a prediction: how many points with wholenumber coordinates (not including (0, 0)) will the line connecting (0, 0) to (12, 15) pass through? Test your prediction to see if you are correct. lowest common multiple (LCM) d 126 ⴜ 30 prime factor Highest common formula Using your answers from Q6 and Q7, or otherwise, copy and complete this table. Number a Number b 30 42 30 100 180 210 HCF aⴛb LCM Write down a formula for the LCM. Can you explain why it works? prime factor decomposition 1.3 Prime factor decomposition 9 .4 Sequences Generate and describe integer sequences Generate and predict terms from practical contexts Why learn this? A mathematical sequence is a list of numbers which follow a rule or pattern. The numbers in a sequence are called the terms of the sequence. Level 5 Sequences can descr ibe in numbers how things grow or develop – from th e size of an insec t population to the spread of a forest fi re. A term-to-term rule tells you what to do to each term to obtain the next term in a sequence. Level 5 An arithmetic sequence starts with a number, a, and adds on or subtracts a constant difference, d, each time. The numbers change in equal-sized steps Level 5 Super fact! To find the rule for a sequence, look at the differences between consecutive terms – the difference pattern. Level 5 Not all sequences have equal-sized steps. For example 1 4 9 16 … ⴙ3 ⴙ5 The Fibonacci sequence is a set of numbers which appears all over nature. It can be used to express the arrangement of a pine cone or how fast some species reproduce. Level 6 ⴙ7 Level 5 For each sequence, identify the term-to-term rule and write the next two terms. ⴙ3 4 ⴙ3 7 ⴙ3 10 13 Term-to-term rule: add 3 The next two terms are 13 + 3 = 16 and 16 + 3 = 19 a 11, 15, 19, 23, … b 19, 16, 13, 10, … c 5, 6.5, 8, 9.5, … d 2.5, 2.6, 2.7, 2.8, … e 2, 4, 8, 16, … f 1, ⴚ1, 1, ⴚ1, … g 200, 100, 50, 25, … h 9, 3, 1, _31 , … Look at these growing rectangles. I can continue or generate a sequence and use a term-to-term rule Watch out! A term-to-term rule could contain ‘add’, ‘subtrac t’, ‘multiply’ or ‘divide’. a Draw the next rectangle in the sequence. b Write down the number of squares in each rectangle. c Does this sequence increase in equal steps? Describe what is happening each time. d How many squares will be in the 5th and 6th rectangles? The first term of a sequence is 3, and the term-to-term rule is ‘square the number and add 1’. What are the next two terms in the sequence? 10 Getting things in order arithmetic sequence difference pattern flow chart Which of these sequences are arithmetic sequences? Copy them and identify the values of a and d for each sequence. a c b 3, 5, 7, 9, … 1, 4, 9, 16, … d 10, 7, 4, 1, … 7, 17, 27, 37, … Write the sequence generated by this flow chart. Is it an arithmetic sequence? Start with 4 Is your answer bigger than 50? Add 13 Yes Level 5 Learn this In an arithmetic sequence, a is the first term and d is the constant difference that is added on each time. If the sequence is decreasing, d is a negative number. STOP I can recognise and describe an arithmetic sequence I can generate a sequence from a flow chart I can recognise and describe an arithmetic sequence I can generate a sequence from a practical context No Steph is making some terraced houses out of rods. a Draw the next picture. b Copy and complete the table. Number of houses Number of rods 1 6 2 3 4 5 6 c Describe this sequence with a term-to-term rule. d Is this sequence arithmetic? If so, write down the values of a and d. George wants to model the spread of a forest fire. He starts by colouring in one square in his book. The fire will spread to another square if it shares an edge with a square that is already on fire. I can predict and test the next term in a practical sequence a Copy and complete the table. Term number Squares on fire b c d e f 1 1 2 3 Predict the number of ‘squares on fire’ for the 4th and 5th terms. Draw the fourth term to test your prediction. What is happening each time? Explain your answer. Describe this sequence with a term-to-term rule. Is this sequence arithmetic? If so, write down the values of a and d. Copy these sequences and write the next two terms. A a 3, 4, 6, 9, … b 100, 99, 97, 94, … c 5, 7, 11, 17, … d 2, 8, 18, 36, … e 49, 36, 25, 16, … f 1, 8, 20, 37, … B Look and say A sequence begins like this. 1, 11, 21, 1211, 111221, ... What is the next number in the sequence? Hint: There is a clue in the title. generate predict sequence Level 6 I can continue a non-arithmetic sequence Fired up George used a square-based system to model a forest fire in Q7. Repeat his experiment using equilateral triangles. (You may like to use isometric paper.) Does the fire spread faster or slower? What real-world situations might this model? term term-to-term rule 1.4 Sequences 11 .5 Generating sequences using rules Generate a sequence using a term-to-term rule Generate a sequence using a position-to-term rule Why learn this? Position-to-term rules can help you predict future ins tances of events that follow se quences – such as solar eclip ses. The term number tells you the position of that term in the sequence. Level 5 A position-to-term rule tells you what to do to the term number to obtain that term in the sequence. Level 5 & Level 6 A position-to-term rule can be written in words or in algebra. For example, 3n ⴙ 5: n is the term number, so to find a term multiply its term number by 3 and add 5. Level 5 & Level 6 Level 5 Each of the arithmetic sequences below has one mistake. Rewrite the sequence correctly and identify a (the first term) and d (the constant difference). a 3, 7, 11, 16, … b 5, 12, 20, 26, … c I can recognise and describe an arithmetic sequence 12, 10, 6, 3, … In an arithmetic sequence, the 3rd term is 15 and the 5th term is 23. What are the values of a and d for this sequence? In another arithmetic sequence, the 3rd term is 18 and the 7th term is 10. What are the values of a and d for this sequence? Use the position-to-term rules to find the 1st, 2nd, 3rd and 10th terms of these sequences. Multiply the term number by 2. When term number = 1, term = 1 × 2 = 2. When term number = 2, term = 2 × 2 = 4. When term number = 3, term = 3 × 2 = 6. When term number = 10, term = 10 × 2 = 20. a Multiply the term number by 5. b Multiply the term number by 3 and add 2. Watch out! Don’t confuse term-to-term and position-to-term rules! c Multiply the term number by 7 and subtract 4. d Divide the term number by 2 and add 5. 12 Getting things in order arithmetic sequence I can find a term given its position and a position-to-term rule decrease generate Level 6 Use the position-to-term rules to find the 1st, 2nd, 3rd and 100th terms of these sequences. I can find a term given its position and a position-to-term rule using positive and negative numbers a Multiply the term number by ⴚ3. b Multiply the term number by 2 and subtract 7. c Subtract 3 from the term number and then multiply by 8. d Subtract the term number from 10. e Divide the term number by 4. I can find a term given its position and an algebraic position-to-term rule Use the position-to-term rules to find the 1st, 2nd, 3rd and 7th terms of these sequences. 5n ⴙ 2 Tip 1st term = 5 × 1 + 2 = 7 2nd term = 5 × 2 + 2 = 12 3rd term = 5 × 3 + 2 = 17 7th term = 5 × 7 + 2 = 37 a 4n ⴚ 3 b 100 ⴚ n c 7n ⴙ 99 d 6n ⴚ 8 e 3 ⴚ 2n f nⴜ2 If the number before n is positive, the sequence is increasing. If it is negative, the sequence is decreasing. a For each of these position-to-term rules, write the first five terms. 5n ⴙ 7 4n ⴚ 2 6n ⴙ 1 ⴚ3n ⴙ 2 b What do you notice about the term-to-term rule and the position-to-term rule in each case? Match each term-to-term definition to a position-to-term definition. Term-to-term a Start at 3, add 2 each time. Position-to-term Multiply the term number ii by 4 and subtract 2. Tip Find the first few terms of each sequence. b Start at 4, subtract 3 each time. Multiply the term number by ⴚ3 and add 7. c Start at 2, add 4 each time. Double the term number and add 1. I can understand and use algebraic position-to-term rules True or false? a The sequence 7n produces the multiples of 7. b Every term in the sequence 2n ⴙ 3 is odd. c The sequence 5 ⴚ n is a decreasing sequence. d The sequences 2(n ⴙ 4) and 2n ⴙ 8 are not the same. e Every term in the sequence 3(100 ⴚ n) is positive. A B Can you digit? The digits 1 to 8 can be arranged as an arithmetic sequence of two-digit numbers like this. 12, 34, 56, 78 (start at 12, add 22 each time) Find another way to arrange the digits 1 to 8 as an arithmetic sequence of two-digit numbers. increase position-to-term rule sequence Rows by any other name Calculate the first five terms of the sequence with the position-to-term rule _1 n(n ⴙ 1). By what name are these 2 numbers better known? term 1.5 Generating sequences using rules 13