Textbook 5C p8 Unit 12: Decimals, Lesson 1 Adding and ...€¦ · Adding and subtracting decimals 2 ... Unit 12: Decimals, Lesson 2 M01 PowerMaths Practice Bk 5C 90347 U12.indd 9

1 Find the totals of these decimals.

a) 0.4 + 0.5 =

b) 0.7 + 0.1 + 0.1 =

c) 0.3 + 0.1 + 0.3 = d) 0.5 + 0.5 =

2 Max cuts some pieces of string. He measures the lengths.

a) How much longer is A than B? – =

b) What is the difference between A and C? – =

Adding and subtracting decimals 1

10 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

0.4 0.5

10 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

0.7

10 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

10 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

AB

C

6

➜ Textbook 5C p8Unit 12: Decimals, Lesson 1

M01 PowerMaths Practice Bk 5C 90347 U12.indd 6 21/08/2018 17:35

3 Complete the part-whole models.

4 Complete the calculations.

a) 0.3 + 0.5 = f) 0.7 – = 0.2

b) 0.7 + 0.1 = g) 0.4 + 0.3 + 0.2 =

c) 0.2 + = 0.5 h) 0.7 + 0.2 – 0.3 =

d) 0.5 – 0.1 = i) 0.9 – 0.1 + 0.2 =

e) 0.8 – 0.2 = j) 0.5 – 0.2 – 0.3 =

5 Complete the following calculations.

a) 0.3 + 0.7 = c) + 0.1 = 1 e) 1 – 0.5 =

b) 0.6 + = 1 d) 1 – 0.2 = f) 1 – = 0.2

6 Complete the addition pyramids. Each row of the pyramid must total the same as the other rows.

a) b) c) d)

0.8 0.8

0.1

0.8 0.8

0.3

0.1 0.2 0.3

0.4

0.2 0.1

0.8

0.5

0.1

0.9

0.2

0.1

7

Unit 12: Decimals, Lesson 1


Refl ectEmma calculates 0.4 + 1 = 0.5. Explain the mistake Emma has made.

8 Write the numbers 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 in the circles so that the sum of each side of the triangle is equal to 0.9. Use each number once.

7 If ◆ and ▲ are two decimal numbers less than 1 and ▲ – ◆ = 0.3, what could ▲ and ◆ be?

▲ = ◆ = .

8



1 Mo adds different amounts of water and orange to make orange squash. Complete the additions.

a) 0.36 l + 0.22 l = l

b) 0.25 l + 0.47 l = l

c) 0.55 + 0.31 = d) 0.38 + 0.38 =


O • Tth Hth

•0.1 0.1 0.1 0.01 0.01 0.01 0.01 0.01

0.01

• 0.1 0.1 0.01 0.01

O • Tth Hth

• 0.1 0.1 0.01 0.01 0.01 0.01 0.01

•0.1 0.1 0.1 0.1 0.01 0.01 0.01 0.01 0.01

0.01 0.01

0.36 l 0.22 l

Water Orange

O . Tth Hth0 . 3 6

+ 0 . 2 2.

O . Tth Hth0 . 2 5

+ 0 . 4 7.

O . Tth Hth0 . 5 5

+ 0 . 3 1.

O . Tth Hth.

+ ..

2 Kate works out 0.05 + 0.12 as a column addition. Explain Kate’s mistake.

O . Tth Hth0 . 5

+ 0 . 1 20 . 6 2

9



3 A running race is 0.65 km long. Lee runs 0.34 km. How far is left to run?

0.65 km – 0.34 km = km

4 Complete the subtractions.

a) 0.92 – 0.58 =

c) 0.71 – 0.24 =

b) 0.49 - 0.19 = d) 0.60 – 0.45 =

O • Tth Hth

•0.1 0.1 0.10.1 0.1

0.1

0.01 0.01 0.01 0.01 0.01

O . Tth Hth0 . 6 5

– 0 . 3 4.

O . Tth Hth0 . 9 2

– 0 . 5 8.

O . Tth Hth0 . 4 9

– 0 . 1 9.

O . Tth Hth0 . 7 1

– 0 . 2 4.

5 Complete the missing numbers in these models.

a) b) c)

0.28

0.09

0.34

0.66

0.35

0.67

10



Refl ectExplain how Alex can use 37 + 59 to fi nd the sum of 0.37 and 0.59.

7 Use four different digits from 1, 2, 3, 4, 5, 6, 7, 8, 9 to:

a) Make the greatest total you can, less than 1.

b) Make the greatest difference you can, less than 1.

6 Ambika is using a number line to work out a calculation.

What two possible calculations might Ambika be working out?

0 .

+ 0 .

0 .

0 .

– 0 .

0 .

10 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

+ 0.05 + 0.52

0.15 0.72

11



1 Use the hundredths grids to help you fi nd the missing numbers.

a) 0.8 + = 1 b) 0.69 + = 1

2 Draw lines to match the pairs that make 1 m when added together.

You may not be able to fi nd a pair for all of the pieces.


0.76 m 0.88 m

0.12 m 0.234 m 0.55 m

0.34 m 0.332 m 0.1 m

0.9 m

0.766 m 0.777 m

12



3 Lexi has made a number on a place value grid.

What mistake has Lexi made?

What counters does she need to add?

4 a) Find the missing numbers.

i) ii) iii)

b) For part i) complete 4 number sentences.

0.38 + = 1 + = 1

1 – = – =

5 Complete the following.

a) 0.3 + = 1 d) 0.90 + = 1 g) 1 – 0.24 =

b) 0.71 + = 1 e) + 0.787 = 1 h) 1 – = 0.07

c) + 0.05 = 1 f) 0.912 + = 1 i) 1 – 0.235 =

O • Tth Hth•

I need to add 0.84 to make 1.

0.38

1

0.384

1

0.380

1

Lexi

0.1 0.1 0.01 0.01 0.01

0.01

0.01 0.01

13



Refl ectAndy says, ‘0.207 + 0.793 = 1.’ Do you agree? Explain your answer.

6 Work out the missing numbers.

a) 0.4 + = 1 b) 0.4 + = 1

0.04 + = 1 0.40 + = 1

0.004 + = 1 0.400 + = 1

7 a) Use six digits from 1, 3, 4, 5, 7, 8 to make two decimal numbers that add up to 1. You can use the same digit more than once but not within the same number.

O . Tth Hth Thth0 .

+ 0 .

1 . 0 0 0

b) Find two different answers for part a ).

What is the same and what is different about your answers?

14



1 Complete these decimal additions.

a) 0.37 + 0.82 =

b) 0.675 + 0.721 =

c) 0.56 + 0.78 = d) 0.7 + 0.7 = e) 0.82 + 0.78 =


O • Tth Hth

•0.1 0.1 0.1 0.01 0.01 0.01 0.01 0.01

0.01 0.01

•0.1 0.1 0.1 0.1 0.1

0.1 0.1 0.1

0.01 0.01

O • Tth Hth Thth

•

•

0.01 0.01 0.01 0.01 0.01

0.01 0.01

0.001 0.001 0.001 0.001 0.001

0.001

0.01 0.01

0.1 0.1 0.1 0.1 0.1

0.1 0.1 0.1 0.1 0.1

0.1

0.1 0.1

O . Tth Hth0 . 3 7

+ 0 . 8 2.

O . Tth Hth0 . 5 6

+ 0 . 7 8.

O . Tth Hth0 . 8 2

+ 0 . 7 8.

O . Tth0 . 7

+ 0 . 7.

O . Tth Hth Thth0 . 6 7 5

+ 0 . 7 2 1.

15



2 Match each calculation with its answer.

3 How much do the ruler and eraser cost altogether?

The ruler and eraser cost £ altogether.

4 Amal uses the treadmill at the gym.

He thinks he ran further on Thursday than he did from Monday to Wednesday in total. Is Amal correct?

Day Distance

Monday 0.625 km

Tuesday 0.193 km

Wednesday 0.208 km

Thursday 1.25 km

0.23 + 0.84 0.76 + 0.52 1 + 0.17 0.74 + 0.63 0.54 + 0.85

1.39 1.37 1.07 1.28 1.17

£0.89

£0.65

16



Refl ectJamie says, ‘0.5 + 0.6 = 0.11.’ Explain why Jamie is wrong.

6 Use the signs <, = or > to complete each statement. Explain how you worked out your answers.

a) 0.51 + 0.63 0.51 + 0.73

b) 0.7 + 0.4 0.71 + 0.39

5 Write the missing numbers.

a) b) c)O . Tth Hth0 . 4 3

+ 0 . 7. 1

O . Tth Hth0 .

+ . 5 91 . 3 7

O . Tth Hth Thth0 . 7 3 2

+ 0 . 7. 1 3

17



1 There are some books for sale in a charity book shop.

a) How much do the Dictionary and Animals of the World cost altogether?

The total cost is £ .

b) Work out the cost of Learn Spanish and Jed’s Diary.

The total cost is £ .


O . Tth Hth6 . 5 0

+ 4 . 3 1.

O . Tth Hth5 . 7 6

+ 3 . 7 9.

Jed’sDiary

Animalsof theWorld

DictionaryLearnSpanish

£3.79 £6.50 £5.76 £4.31

O • Tth Hth

•

•

1 1 1 1 1

1 1 1 1

1

0.01

0.1 0.1 0.1 0.1 0.1

0.1 0.1 0.1

O • Tth Hth

•

•

1 1 1 1 1

1 1 1

0.01 0.01 0.01 0.01 0.01

0.01 0.01 0.01 0.01 0.01

0.01

0.01 0.01 0.01 0.01

0.1 0.1 0.1 0.1 0.1

0.1 0.1 0.1 0.1 0.1

0.1 0.1

0.1 0.1

2 Complete the additions.

a) 2.3 + 4.6 = b) 3.5 + 5.8 = c) 1.98 + 0.77 =

O . Tth2 . 3

+ 4 . 6.

O . Tth.

+ ..

18



3 Work out the totals and use the >, < or = sign to complete each number sentence.

a) 0.502 + 4.165 3.258 + 0.875 b) 8.62 + 6.18 2

.63 + 1.71 + 3.26

4 Zac wants to buy the scarf and the magazine.

He adds the amounts.

What mistake has Zac made? What is the correct answer?

T O · Tth Hth1 1 . 2

3 . 6 94 . 8 1

1

5 Find the answers. Mark them on the correct place on the number line.

4.5 + 2.8 = 2.75 + 4.82 = 1.823 + 6.077 =

8.07 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9

£3.69£11.20

19



Refl ectExplain how to add 4.53 and 3.78.

6 Reena’s dad wants to take Reena and her little sister somewhere for her birthday. He has £50. Which activities can they afford to do?

Theatre Cinema Zoo Circus

Adult £29.50 £15.69 £19.90 £16.60

Child £9.75 £5.32 £12.50 £8.80

20



1 Danny buys a bottle of milk and loaf of bread.

The milk costs £1.05. The total cost of his items is £2.54

a) How much did the loaf of bread cost?

The loaf of bread costs £ .

b) Danny gives the shop keeper £2.70.

How much change does he get?

Danny gets £ change.


a) 5.4 – 3.2 = b) 7.26 – 4.83 = c) 2.661 – 0.625 =


O • Tth Hth1 1 • 0.1 0.1 0.1 0.1 0.1 0.01 0.01 0.01 0.01

O . Tth Hth2 . 5 4

– 1 . 0 5.

O . Tth Hth.

– ..

O . Tth5 . 4

– 3 . 2.

21




a) 7.56 – 0.49 = b) 12.52 – 3.92 =

O . Tth Hth6 . 2 0

– 0 . 5 95 . 7 9

5 1

5 Holly is walking 24.5 km for charity. By 3 pm she has walked 18.7 km.

How much farther does Holly have to walk?

Holly has km left to walk.

4 Kate has £6.20 in her pocket. She buys a bottle of water for 59p.

Kate does this calculation to work out her change.

What mistake has she made?

22



Refl ectWhat is the same and what is different about these calculations? Explain how you would work out the answer to each one. a) 5.8 – 3.2 b) 5.8 – 3.9

7 How much greater is the difference between A and C than the difference between B and C?

The difference between A and C is greater than between B and C.

6 Complete the additions.

a) 3.21 + = 5.49

b) 12.99 = + 5.32 + 2.69

1000

A11.58

B68.65

C81.96

23



1 Bella fl ies a paper plane 2.31 m. Ebo’s paper plane fl ies 0.7 m.

How much further did Bella’s paper plane fl y?

Bella’s plane fl ew m further than Ebo’s plane.


O . Tth Hth2 . 3 1

– 0 . 7 0.

O . Tth Hth3 . 6 2

– 4 . 8.

O . Tth Hth Thth1 . 9 6

– 1 . 2 5 8.

2 Work out the following calculations.

a) 3.62 + 4.8 = b) 1.96 – 1.258 =


a) 4.7 + 33.64 = b) 9.5 + 1.872

24

Unit 12: Decimals, Lesson 7➜ Textbook 5C p32


6 Is Danny’s statement true?

Answer always, sometimes or never.

Give some examples to support your answer.

4 a) 16.9 – 11.87 = b) 118.7 – 3.95 =

T O . Tth Hth5 3 . 4 9

– 3 . 75 0 . 4 2

Subtracting a number with 2 decimal places from a number with 1 decimal place will give an answer with 2 decimal places.

Danny

5 Zac is working out 53.49 – 3.7. Can you explain the mistake in his calculation? What is the correct answer?

53.49 – 3.7 =

25



Refl ectWhat are the most important things to remember when adding or subtracting decimals with a different number of decimal places?

8 These two cards have a difference of 1.55. What could the sum of the two cards be?

How many answers can you fi nd?

7 Compare the number lines and fi nd the difference between A and B.

4.1

A

4.2B

15 16

19.7

The difference between A and B is .

26



1 Ebo is working out 6 + 1.37. He makes both numbers using place value counters and then adds the numbers.

a) What answer did Ebo get?

b) Explain a different way Ebo could fi nd the answer.

2 All these calculations have the same answer. Find the missing numbers.

12 + 2.72 = 5 + .72 =

3 + 11. = 0.72 + =

5 + 5 + = 14.7 + =

3 Complete the column subtractions.

a) 7 – 3.8 = b) 12 – 4.35 =


T O . Tth Hth1 2 . 0 0

– 4 . 3 5.

O . Tth Hth6 . 0 0

+ 1 . 3 7.

O . Tth7 . 0

– 3 . 8.

O • Tth Hth

•

•

1 1 1 1 1

1

1

0.01 0.01 0.01 0.01 0.01

0.01 0.01

0.1 0.1 0.1

27



Suncream

300 ml

4 Bella works out 5 – 2.84 by doing 4.99 – 2.83.

Use Bella’s method to answer these calculations.

a) 8 – 2.807= b) 12 – 4.91 = c) 16 – 1.8 =

5 a) What is the total cost of these items?

The total cost is £

b) Mary uses 18.7 ml of sun cream.

How much is left?

There is ml of sun cream left.

6 Work out the following calculations.

a) 3 + 0.45 = d) 2 + 9 + 3.4 =

b) 17 + 8.725 = e) 380 m + 70.85 m = m

c) 3.67 kg + 7 kg = kg f) 28.513 + 48 + 399 =

£8 £5 £3.92

28



Refl ectHow can you use a number line to show that 7 – 2.4 is the same as 6.9 – 2.3?

8 Work out the missing numbers.

a) 8 – 3.92 = 4 + b) 7.9 – 5.42 = 12 –

7 How much more milk than lemonade is there?

There is ml more milk than lemonade. 6 litres

1 litre 1.75 litre

4 litres

2 litres

29



1 Work out the missing numbers in each sequence.

a) 4.6, 4.7, 4.8, , , ,

b) 11.5, 11.9, , 12.7, , 13.5, ,

c) , , 15.65, 15.6, 15.55, ,

2 Complete the numbers on the number line.

a)

b)

3 Kate is counting up by the same amount each time.

Decimal sequences

0, 0.3, 0.6, 0.9, 0.12, 0.15

0.76 0.77

5.615 5.620 5.630 5.645

Kate

What mistake has Kate made?

30



4 Complete the sequence and write whether each rule is true or false.

a) 10.1, 10.3, 10.5, 10.7, c) 3.0, 2.25, 1.5, 0.75,

The rule is ‘add 0.2’. The rule is ‘subtract 0.25’.

b) 39.57, 39.60, 39.63, 39.66, d) 0.4, 0.52, 0.64, 0.76,

The rule is ‘add 0.3’. The rule is ‘add 0.12’.

5 Max is counting up by 0.02 each time. He starts at 12.45.

a) What are the next three numbers Max will say?

The next three numbers Max will say are ,

,

.

b) Max stopped when he reached the fi rst number above 18.

What number did Max stop on?

6 Complete the sequences. Write the rule for each sequence.

a) 0.21, 0.42, 0.63, , 1.05, 1.26,

b) 11.3, , 12.1,

,

, 13.3, 13.7

c) 7.68, 7.61, 7.54, 7.47, ,

, 7.26

Rules:

a)

b)

c)

Max

12.45, 12.47 …

31



Refl ectMake a sequence using decimal numbers. Ask a partner to continue the sequence. What rule did you use?

7 Seven cones are spaced equally apart for a running race.

In round 1, Toshi starts at A, runs to B and then back to A.

In round 2, he then runs from A to C and back to A.

He continues in the same pattern until round 6, when he runs A to G and back to A.

Complete the table to show how far Toshi runs each round and in total.

Round 1 2 3 4 5 6

Distance travelled in round (km)

Total distance travelled so far (km)

7 Seven cones are spaced equally apart for a running race.


Seven cones are spaced equally apart for a running race.
























A B C D E F G

0.4 km 0.4 km 0.4 km 0.4 km 0.4 km 0.4 km

32



1 Work out the missing values on the bar models.

a)

b)

c)

Problem solving – decimals 1

54.47 kg 44.305 kg

80.36 m

24.98 m

£ £12.67 £15.03

£28.98

kg

m

33



Refl ect

2 Toshi drives 26.3 km to work. He then drives 6.85 km to his gran’s house.

How far does he drive in total?

Toshi drives km in total.

3 What is the mass of the grape?

The mass of the grape is g.

4 Circle the two numbers that add up to 1.2 but have a difference of 0.78.

18.4 g 20.95 g

1.120.8 0.12 0.21 0.90 0.99

34



Refl ectLook at the bar models in question 1. Write a question that you could solve using one of the bar models.

6 Isla has £20. She spends £3.20 on a magazine. She then buys a book that costs £5.90 more than the magazine.

How much change should Isla receive in total?

5 Complete the calculation.

100 – 1.0 – 0.1 – 0.01 – 0.001 =

35



1 Amelia buys three items.

How much do the three items cost in total?

The total cost of the three items is £ .

2 Danny buys two items for his dog. He buys a chew toy costing £4.67 and a lead that costs £2.85 more than the chew toy. He pays with a £20 note.

How much change does Danny get?

£12.50

Problem solving – decimals 2

£12.50 £4.79 £0.75

?

£0.75£4.79

36



3 A bucket has 8.751 l of water in it. Amal pours a further 7.5 l into the bucket. 1.27 l of water spill out because the bucket is full.

How much water does the bucket hold?

4 Choose three numbers from the cards that make the calculation true.

+ – = 10

5 Three identical rectangles are put together with their edges touching.

What is the length of the side marked A?

0.345 2.233 3.578 8.655 12.178

2.65 m

1.9 m

A

37



Refl ectWrite a problem-solving question with the answer 3.21 kg. Ask your partner to check the answer.

7 Kate and Richard have both saved some money.

Richard needs to save another £1.20 to make £100.

After paying £24.78 for stationery, Kate has £36.98 less than Richard. How much more money has Richard saved than Kate?

6 When added together, these two cards total 9.2.

What is the difference between the cards?4.59

38



1 Use the place value grids to help you complete these multiplications.

a) 2.4 × 10 = b) 0.13 × 10 =

2 Complete the multiplications.

a) 1.3 × 10 = c) 13.5 × 10 =

b) 1.35 × 10 = d) 0.135 × 10 =

Multiplying decimals by 10

T O • Tth1 1

1 1

1 1

1 1

1 1

1 1

1 1

1 1

1 1

1 1

•

0.1 0.10.1 0.1

0.1 0.10.1 0.1

0.1 0.10.1 0.1

0.1 0.10.1 0.1

0.1 0.10.1 0.1

0.1 0.10.1 0.1

0.1 0.10.1 0.1

0.1 0.10.1 0.1

0.1 0.10.1 0.1

0.1 0.10.1 0.1

O • Tth Hth

•

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.01 0.01 0.01

0.01 0.01 0.01

0.01 0.01 0.01

0.01 0.01 0.01

0.01 0.01 0.01

0.01 0.01 0.01

0.01 0.01 0.01

0.01 0.01 0.01

0.01 0.01 0.01

0.01 0.01 0.01

H T O • Tth Hth Thth

1 • 3

•


1 • 3 5

•


0 • 1 3 5

•


1 3 • 5

•

39



3 Olivia says, ‘14.8 × 10 = 14.80.’

What mistake has Olivia made?

What is the correct answer?

4 Draw lines to match each multiplication to its answer.

5 Complete the multiplications.

0.003 × 10 3.53 × 10 0.03 × 10 10 × 0.353 0.3 × 10 10 × 3.003 0.0353 × 10

0.03 3 35.3 30.03 0.353 0.3 3.53

a) 5.8 × 10 = h) 0.019 × 10 =

b) 5.82 × 10 = i) = 3.09 × 10

c) 24.9 × 10 = j) 0.04 × 10 =

d) 1.09 × 10 = k) = 3.099 × 10

e) 21.08 × 10 =

l) 0.004 × 10 =

f) 0.198 × 10 = m) = 30.99 × 10

g) 10 × 21.08 =

n) 0.040 × 10 =

40



Refl ectExplain what happens to the digits when you multiply a decimal number by 10.

7 Mo’s stride is 0.8 metres long. Lexi’s stride is 0.65 metres long. They each take 20 strides.

How much further has Mo travelled than Lexi?

Mo has travelled m further than Lexi.

6 a) Luis is working out the missing number in × 10 = 12.5.

He thinks the missing number is 125. Is Luis correct? Explain your answer.

b) Work out the missing numbers.

× 10 = 15 × 10 = 9.2 × 10 = 1.73

× 10 = 25 10 × = 15.2 × 10 = 17.3

41



1 Complete the place value grids to work out the answers.

a)

7.9 × 10 =

7.9 × 100 =

7.9 × 1,000 =

b)

2.19 × 10 =

2.19 × 100 =

2.19 × 1,000 =

c) 0.84 × 100 = e) 0.05 × 100 =

d) 0.7 × 1,000 = f) 1,000 × 1.7

Multiplying decimals by 10, 100 and 1,000

Th H T O • Tth Hth

7 • 9

•

•

•


2 • 1 9

•

•

•


0 • 8 4

•


0 • 7

•


•

•


•

•

42




a) 0.4 × 100 = c) × 100 = 912

0.04 × 100 = × 100 = 91.2

0.004 × 100 = × 1,000 = 9.12

100 × 0.4 = 1,000 × = 91.2

b) 1.7 × 100 = d) 4.5 × = 450

1.7 × 1,000 = 0.045 × = 4.5

0.17 × 1,000 = 0.045 × = 0.45

0.045 × = 45

3 a) Sofi a buys 1,000 cans of orange juice for the school café. One can contains 0.335 litres of juice.

How many litres of orange juice did Sofi a buy?

b) The length of a blue straw is 0.11 m. The length of a red straw is 0.09 m.

What is the total length of 100 blue and 100 red straws?

43



5 Use the number cards to fi nd three ways to complete each calculation.

a) × = 68 b) × = ×

× = 68 × = ×

× = 68 × = ×

4 Complete the missing numbers in this multiplication grid.

Number 0.38 0.012

× 3.6 380 76.91

× 12.07 1.2

10 100 1,000 6.8 0.68 0.068

Refl ect

Complete the sentences:

• Multiplying by 100 is the same as multiplying by and again.

• Multiplying by 1,000 is the same as multiplying by and

and again.

Show your partner how you can use a place value grid to multiply by 100 or 1,000.

44



1 Use the place value grids to help you work out the divisions.

1.2 ÷ 10 =

Dividing decimals by 10

O • Tth Hth1 • 0.1 0.1

O • Tth Hth

•

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.01 0.01

0.01 0.01

0.01 0.01

0.01 0.01

0.01 0.01

0.01 0.01

0.01 0.01

0.01 0.01

0.01 0.01

0.01 0.01

T O • Tth Hth

1 • 2

•

Th H T O • Tth Hth4 • 5

•

Th H T O • Tth Hth4 5 •

•


•

•


•

•

2 Work out these divisions.

a) 4.5 ÷ 10 = c) 45 ÷ 10 =

b) 0.45 ÷ 10 = d) 4.52 ÷ 10 =

45



3 What number should go in each part of the bar?

÷ =

4 10 apples have a total mass of 2.8 kg. Each of the apples has the same mass.

What is the mass of one apple?

The mass of one apple is kg.

5 Work out the following missing numbers.

a) 603 ÷ 10 = d) 75.3 ÷ = 7.53 g) 0.035 = ÷ 10

b) 160.3 ÷ 10 = e) ÷ 10 = 0.08 h) 8.719 = ÷ 10

c) 16.31 ÷ 10 = f) 3.978 ÷ 10 = i) 3.895 × 10 = ÷ 10

6 Is Max correct? Explain any mistakes.

? ? ? ? ? ? ? ? ? ?

2.31

Max

10 books costs £35, so each book costs £3.5.

46



Explain how to divide a decimal number by 10.Explain how to divide a decimal number by 10.Explain how to divide a decimal number by 10.Explain how to divide a decimal number by 10.

Refl ect

8 Toshi has 2.5 kg of hot chocolate powder. He makes 10 cups of hot chocolate every week for 10 weeks before it runs out.

How much does he use in each cup? Give your answer in kg.

Toshi uses kg of hot chocolate powder in each cup.

7 a) What is the cost of 100 ml of lemonade?

100 ml of lemonade costs £ .

b) What is the cost of 200 g of cocoa? Explain your answer.

200 g of cocoa costs £ .

1 l1 kg

£1.80

£12

47



1 Use the place value grids to answer these questions.

a) 23 ÷ 100 = c) 5.2 ÷ 100 =

b) 145 ÷ 1,000 = d) 13 ÷ 1,000 =

2 Use the tenths grid to show if Bella is correct.

Explain your answer.

Dividing decimals by 10, 100 and 1,000

Dividing by 10 and then 10 again is the same as dividing by 100.


•

•


•

•


2 3 •

•


5 • 2

•

Bella

48



3 Write true or false under each calculation. Correct those that are incorrect.

a) 9 ÷ 100 = 0.09 c) 53 ÷ 100 = 0.053 e) 8.7 ÷ 100 = 0.87

b) 7 ÷ 1,000 = 0.007 d) 75 ÷ 1,000 = 0.075 f) 9.1 ÷ 1,000 = 0.00091

0.8 ÷ 100 0.18 ÷ 100 10.8 ÷ 100 0.108 ÷ 10

108 ÷ 1,000 0.08 ÷ 100 8 ÷ 1,000 1.8 ÷ 1,000 1.08 ÷ 100


a) 3.7 ÷ = 0.37 b) ÷ 10 = 0.12

3.7 ÷ = 0.037 ÷ 100 = 0.12

3.7 ÷ = 0.0037 ÷ 1,000 = 0.12

4 Draw lines to match the calculations that give the same answer. Not all have a pair.

49



My journal

Refl ectReena thinks that 0.351 ÷ 10 = 3.51 ÷ 100 and 3.51 ÷ 100 = 35.1 ÷ 1,000. Is Reena correct? Explain your answer.

7 Each shape represents a different number. Find the missing values.

■ ÷ 10 = ▲ × 100 = 0.098 ★ × 10 = 0.61 ÷ 100 = ●

■ = ★ =

▲ = ● =

6 Each day Zac and Jamie put some money in their money box.

After 100 days Zac has £18 and Jamie has £124.

If they always put in the same amount each day, how much more money did Jamie save each day in pounds?

Jamie saved £ more each day.

50



End of unit check

My journal

1 Max is working out 12 – 4.35.

a) Show two different ways Max could do this.

What advice would you give Max?

b) What mistakes should Max be careful not to make when subtracting

decimals?

➜ Textbook 5C p68

51

Unit 12: Decimals


Power check

How do you feel about your work in this unit?

2 What is the same and what is different about these calculations?

25 + 2.95 12.47 + 13.48 18.3 + 9.65

52

Unit 12: Decimals


Power play

The aim is to fi nd a path from 2 to 0.002.

How many different paths can you fi nd? Use the place value grid to help you.

Now fi nd a route where the answer is 2!

TTh Th H T O • Tth Hth Thth

•

•

2 ÷ 100 ÷ 10 × 100 × 10 ÷ 100

÷ 1,000 × 100 × 10 ÷ 10 × 100 × 10

× 10 ÷ 100 × 10 ÷ 10 × 100 ÷ 1,000

× 100 ÷ 10 × 1,000 × 100 × 10 2

2 ÷ 100 ÷ 10 × 100 × 10 ÷ 100

÷ 1,000 × 100 × 10 ÷ 10 × 100 × 10

× 10 ÷ 100 × 10 ÷ 10 × 100 ÷ 1,000

× 100 ÷ 10 × 1,000 × 100 × 10 0.002

Explain your method.

53

Unit 12: Decimals


Documents

Textbook 5C p8 Unit 12: Decimals, Lesson 1 Adding and ...€¦ · Adding and subtracting decimals 2 ... Unit 12: Decimals, Lesson 2 M01 PowerMaths Practice Bk 5C 90347 U12.indd 9