Class Book. Anita Straker, Tony Fisher, Rosalyn Hyde, Sue Jennings and Jonathan Longstaffe

Transcription

1 Class Book Anita Straker, Tony Fisher, Rosalyn Hyde, Sue Jennings and Jonathan Longstaffe 5

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3 Contents Tier 5 N5.1 Powers and roots 1 1 Integer powers of numbers 1 Estimating square roots 3 3 Prime factor decomposition 6 How well are you doing? 9 A5.1 Sequences and graphs 11 1 Generating sequences 11 Making generalisations 15 3 Using computers 18 4 Sketching linear graphs 0 5 Rearranging linear equations 4 6 Graphs using real-life contexts 7 How well are you doing? 30 G5.1 Measures and mensuration 33 1 Perimeter and area 33 Finding 37 3 Area of a circle 40 4 Solving circle problems and using 4 5 Volume of prisms 45 6 Surface area of prisms 48 How well are you doing? 51 Functional skills 1 54 N5. Proportional reasoning 56 1 Adding and subtracting fractions 56 Multiplying fractions 59 3 Dividing fractions 60 4 Percentage change 6 5 Ratio 65 6 Direct proportion 69 How well are you doing? 73 S5.1 Enquiry Stem-and-leaf diagrams 75 Starting a statistical investigation Completing a statistical investigation Data collection sheets 83 5 Starting a statistical investigation 87 6 Completing a statistical investigation 90 How well are you doing? 93 A5. Equations and formulae 95 1 Multiplying out brackets 95 Factorising expressions 97 3 Substituting into formulae 99 4 Changing the subject of a formula Solving linear equations Trial and improvement 107 How well are you doing? 110 Functional skills 11 G5. D and 3D shapes Exploring angles and lines 114 Solving problems Solving longer problems Drawing 3D objects 1 5 Drawing plans and elevations 14 6 More plans and elevations 16 7 Solving problems using surface area and volume 19 8 Surface area and volume of prisms 13 How well are you doing? 134 N5.3 Calculations and calculators Powers of Rounding and approximation Mental calculations with decimals Written calculations with decimals Using a calculator Problems involving measures 150 How well are you doing? 153 S5. Probability Simple probability 155 Equally likely outcomes with two events Mutually exclusive events Practical probability experiments Simulating probability experiments 166 How well are you doing? 168 A5.3 Functions and graphs Generating linear graphs using ICT 170 Sketching graphs 17 Tier 5 Class book Contents iii

4 3 Drawing accurate graphs Direct proportion Reflecting graphs in y = x Simple quadratic graphs using ICT 183 How well are you doing? 185 G5.3 Transformations Planes of symmetry 187 Combined transformations Islamic patterns Enlargements Enlargements in real-life applications Length, area and volume 03 How well are you doing? 08 A5.4 Using algebra 11 1 Using graphs to solve problems 11 Using algebra in geometry problems 14 3 Using algebra in investigations 16 How well are you doing? 18 Functional skills 3 0 S5.3 Enquiry 1 Calculating statistics Line graphs for time series 4 3 Scatter graphs 7 4 Collecting and organising data 30 5 Analysing and representing data 3 6 Interpreting data 34 7 Reporting and evaluating 35 How well are you doing? 39 G5.4 Angles and constructions 4 1 Angles in polygons 43 Regular polygons 46 3 Regular polygons and the circle 47 4 Angle problems and polygons 49 5 Polygons and parallel lines 53 6 Constructions 57 7 Constructing triangles 60 8 Loci 64 9 More loci 67 How well are you doing? 70 A5.5 Equations, formulae and graphs 7 1 Factorising 7 Working with algebraic fractions 76 3 Working with formulae 79 4 Forming equations 81 5 Visualising graphs 84 6 Interpreting graphs 87 7 Matching graphs to real-life situations 90 8 Using graphs to solve problems 9 How well are you doing? 96 Functional skills 4 98 S5.4 Probability Theoretical and experimental probability 300 Mutually exclusive events Using experimental probability Choice or chance? 31 How well are you doing? 314 N5.4 Solving problems History of our number system and zero 316 Number puzzles based on 3 by 3 grids Exploring fractions Problems involving properties of numbers 31 5 Using algebra and counter-examples 33 How well are you doing? 37 R5.1 Revision unit Using a calculator 39 Using percentages to compare proportions 33 3 Sequences, equations and graphs Angles and polygons Charts and diagrams 345 R5. Revision unit Ratio and proportion 351 Solving number problems Expressions, equations and formulae Circles and enlargements Probability 369 Answers 376 Index 380 iv Tier 5 Class book Contents

5 Powers and roots N 5.1 This unit will help you to: calculate whole-number powers of numbers; estimate square roots; write a number as the product of its prime factors; find the highest common factor (the HCF) of two numbers; find the lowest common multiple (the LCM) of two numbers. 1 Integer powers of numbers This lesson will help you to work out integer powers of numbers and use the power keys of a calculator. Exercise 1 The short way to write is as 5, or to the power 5. The small number 5 is called the index. An index can be negative as well as positive. For example: The calculator key to find powers of numbers looks like this: x y. Example 1 Find the value of 6 4. Key in 6 xy 4. The display shows the answer: 196 To multiply two numbers in index form, add the indices, so a m a n a m n. Example Simplify To divide two numbers in index form, subtract the indices, so a m a n a m n. Example 3 Simplify N5.1 Powers and roots 1

6 1 Write each expression in index form. a b c e d ( 1) ( 1) ( 1) ( 1) f 1 6 Work out each value without using your calculator. Show your working. a 6 b ( 3) 5 c 4 4 d ( ) 7 e 1 0 f ( 1) 17 g 4 h Use your calculator to work out each value. Where appropriate, give your answer correct to two decimal places. a 7 4 b 5 6 c 11 3 d 3 9 e ( ) 10 f g h Simplify these. a 5 3 b c d a 5 a 3 e f g h b 5 b 5 A palindromic number reads the same forwards and backwards. Copy and complete this cross-number puzzle. Across Down 1 A square number A square palindromic number A multiple of 13 4 A cube number Some numbers can be written as the sum of three square numbers. For example: Write each of these numbers as the sum of three square numbers. a 19 b 41 c 50 d 65 e 75 f 94 7 Rachel is 3 years older than her sister Hannah. The sum of the squares of their ages in years is 317. How old are Rachel and Hannah? N5.1 Powers and roots

7 Extension problem 8 Find the two smallest whole numbers where the difference of their squares is a cube, and the difference of their cubes is a square. Points to remember The number raised to the power 4 is 4 or. 4 is called the index or power, and 4 is written in index form. To multiply numbers in index form, add the indices, so a m a n a m n. To divide numbers in index form, subtract the indices, so a m a n a m n. A negative number raised to an even power is positive. A negative number raised to an odd power is negative. Estimating square roots This lesson will help you to estimate square roots and to use the root keys of a calculator. Exercise n is the square root of n. For example, You can find positive square roots on a calculator. Example 1 To find 81, press 8 1 _. The display shows the answer: 9 _ On some calculators you press the square-root key first: Some calculators have a cube-root key 3 _. Example 8 1 To find 3 64, press _. The display shows the answer: 4 N5.1 Powers and roots 3

8 You can estimate the positive square root of a number that is not a perfect square. Example 3 Estimate the value of must lie between 64 and 81, so Since 70 is closer to 64 than to 81, we expect 70 to be closer to 8 than to 9. An estimate is You can estimate the value of a square root more accurately using trial and improvement. Example 4 Solve a 135. Value of a Value of a too small too big a is between 11 and too small a is between 11.5 and too small a is between 11.6 and too big a is between 11.6 and too big a is between 11.6 and So a must lie on the number line between 11.6 and Numbers between 11.6 and round down to 11.6 to 1 d.p, so a 11.6 to 1 d.p. 1 Write two solutions to each of these equations. a x 9 b x 49 c x 144 d x 1 Write the value of each of these expressions. Use a calculator to help you. Where appropriate, give your answer correct to two decimal places. a b 3 10 c 3 ( 64) _ d 0.04 e 3 ( 15) f 1.5 g 3 h 3 ( 1) 4 N5.1 Powers and roots

9 3 Estimate the integer that is closest to the positive value of each of these. a _ 6 b 45 c 115 d 70 4 Use your calculator to find the positive value of each of the square roots in question 3. Give your answers correct to one decimal place. 5 A square patio is to be paved with square paving slabs. Only whole slabs will be used. The paving slabs come in packs of packs of slabs are needed to make sure that there are enough slabs. How many slabs are used? 6 Solve these equations by using trial and improvement. Make a table to help you. Give your answers to one decimal place. a a 95 b a 15 c a The area of this square rug is 15 m. Use trial and improvement to find the length of a side correct to two decimal places. Extension problem 8 What is the smallest square number that begins with three 8s? 3 Points to remember n is the square root of n, for example _ n is the cube root of n, for example , N5.1 Powers and roots 5

10 3 Prime factor decomposition This lesson will help you to: write a number as the product of its prime factors; find the highest common factor (the HCF) of two numbers; find the lowest common multiple (the LCM) of two numbers. Did you know that? The Greek mathematician Euclid proved in about 300 BC what is called the Fundamental Theorem of Arithmetic. This shows that every integer can be written as a product of prime factors in only one way. Exercise 3 You can use a division or ladder method to find the prime factors of a number. Example 1 The prime factors of 75 are The prime factors of 4 are You can also use a tree method to find the prime factors of a number Example The prime factors of 48 are You can use prime factors to find the highest common factor (HCF) and the lowest common multiple (LCM) of two numbers. Example 3 The prime factors of 7 are 3 3. The prime factors of 60 are 5 3. These are shown on the Venn diagram. The overlapping or common prime factors give the HCF: All the prime factors give the LCM: N5.1 Powers and roots

11 1 The number 18 can be written as the product of prime factors Write each of these numbers as the product of prime factors. a 1 b 15 c 1 d 4 e 7 f 54 a List all the factors of 50. b Write 50 as the product of prime factors. 3 a List all the factors of 45. b Write 45 as the product of prime factors. 4 Find a number bigger than 50 that has the same number of factors as Using the Venn diagrams below, work out the HCF and LCM of: a 7 and 30 b 50 and 80 c 48 and The prime factors of 10 are,,, 3 and 5. The prime factors of 75 are 3, 5 and 5. Show these numbers on a Venn diagram. Use the diagram to work out the HCF and LCM of 10 and The prime factors of 40 are,, and 5. The prime factors of 90 are, 3, 3 and 5. Show these numbers on a Venn diagram. Use the diagram to work out the HCF and LCM of 40 and a Which prime numbers are factors of both 4 and 54? b What is the biggest number that is a factor of both 4 and 54? c What is the smallest number that is a multiple of both 4 and 54? 9 Find the HCF and LCM of: a 8 and 40 b 00 and 175 c 36 and A four-digit number is a multiple of 1 and a multiple of 35. What is the smallest number that it could be? N5.1 Powers and roots 7

12 Extension problems 11 a What is the smallest number with exactly 3 factors? b What is the smallest number with exactly 5 factors? c What is the smallest number with exactly 7 factors? Exactly 9 factors? 11 factors? 13 factors? 1 Seven friends are having lunch at the same café. The first one eats there every day, the second every other day, the third every third day, the fourth every fourth day, the fifth every fifth day, the sixth every sixth day, and the seventh once a week on the same day. The next time they all meet at the café they are planning to have a lunch party. In how many days from now will the lunch party be? Points to remember Writing a number as the product of its prime factors is its prime factor decomposition. For example, 4 3 or 3 3. The highest common factor (HCF) of a pair of numbers is the largest number that is a factor of each number. For example, 8 and 1 3. The highest common factor is. The lowest common multiple (LCM) of a pair of numbers is the smallest number that is a multiple of each number. For example, 8 and 1 3. The lowest common multiple of 8 and 1 is N5.1 Powers and roots

13 How well are you doing? Can you: work out whole-number powers of numbers? estimate square roots? write a number as the product of its prime factors? find the highest common factor (the HCF) of two numbers? find the lowest common multiple (the LCM) of two numbers? Powers and roots (no calculator) level 6 a Put these values in order of size with the smallest first b Look at this information. 5 5 is 315 What is 5 7? 001 level 6 a Look at these numbers Which is the largest? Which is equal to 9? b Which two of the numbers below are not square numbers? N5.1 Powers and roots 9

14 3 Work out the value of each expression. a b 4 3 c _ Look at these equations. a 4 3 a What is the value of a? b 8 7 b What is the value of b? 5 a Find the highest common factor of 84 and 60. b Find the lowest common multiple of 16 and 36. Powers and roots (calculator allowed) 6 Suzy thinks of a number. She uses her calculator to square the number and then adds 5. Her answer is What is Suzy s number? 7 The three numbers missing from the boxes are different prime numbers bigger than 3. c c c 1045 What are the missing prime numbers? 10 N5.1 Powers and roots