Short Blocks

# Maths Year 5 Spring Decimals and Fractions (A)

Each unit has everything you need to teach a set of related skills and concepts.

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The PowerPoint incorporates step-by-step teaching, key questions, an in-depth mastery investigation, problem-solving and reasoning questions - in short, everything you need to get started.

All the other resources are there to support as-and-when required. Explore at your leisure - and remember that we are always here to answer your questions.

## Unit 1 Place value in decimals; rounding (suggested as 3 days)

### Objectives

Place value in decimals; multiply/divide by 10 and 100; rounding
Unit 1: ID# 5413

National Curriculum
Dec/Fr (vii) (viii) (ix)

Hamilton Objectives
19. Understand the effect of multiplying or dividing by 10, 100, 1000, including 1- and 2-place decimal answers.
29. Write decimal numbers as tenths and hundredths, e.g. 0.71 as 71/100.
30. Locate 2-place decimal numbers on a line; round them to the nearest tenth or whole number.

### Planning and Activities

Day 1 Teaching
Revise place value, quizzing children about the digits in 4.03. Find 4.03 + 0.7. Rehearse writing 2-place decimal numbers. Use place value additions to emphasise the value of each digit, e.g. start with 4.56, add one hundredth, then add two tenths, subtract one whole, subtract four hundredths, subtract four tenths. Ask children to show you the new number each time.
Group Activities
Use the in-depth problem-solving investigation ‘Spiralling Decimals’ from NRICH as today’s group activity.
Or, use these activities:
-- Use place value to add and subtract numbers with two decimal places, one calculation at a time or in longer chains.

Day 2 Teaching
Use the place value grid on the ITP Moving digits to show the effect of multiplying and dividing by 10, 100 and 1000. The digits move to the left when multiplying and to the right when dividing. Emphasise that the decimal point does not move.
Group Activities
-- Explore decimal place value and number order when multiplying and dividing by 10, 100 and 1000.

Day 3 Teaching
Show children a counting stick. Say that one end represents 2; the other 3. Use this to demonstrate that we can round 1-place decimals to the nearest whole number, e.g. we round 2.4 to 2 and 2.7 to 3. Write some 2-place decimals between 2.3 and 2.4 and round these to the nearest tenth, then to the nearest whole number. Probe understanding of rounding: Write a number less than 6 with two decimal places that rounds up to 6, etc.
Group Activities
-- Explore rounding 2-place decimals marked on number lines, or while playing Bingo.

### You Will Need

• Place value grid 10–0.01 (see resources)
• Number cards 0–9
• Flipchart
• Whiteboards and pens
• A4 paper for each child
• ITP: Moving digits
• 3-digit number cards (see resources)
• Place value stars image (see resources)
• Place value dice
• × and ÷ starting numbers (see resources)
• Counting stick

### Mental/Oral Maths Starters

Day 1
1-place decimals (pre-requisite skills)

Suggested for Day 2
Adding to the next whole number from a 1-place decimal number (simmering skills)

Suggested for Day 3
Difference between negative numbers (simmering skills)

### Worksheets

Day 1
Place value additions and subtraction; add and subtract 0.1 and 0.01 and multiples of 0.1 and 0.01.

Day 2
Multiply and divide by 10 and 100.
Multiply and divide by 10, 100 and 1000.

Day 3
Round decimals to the nearest whole number.
Round decimals to the nearest tenth and whole number.

### Mastery: Reasoning and Problem-Solving

• Divide 47,310 by 10 repeatedly until you get a number that is less than 100. Write that number.
• Write the next two numbers in each sequence.
0.41 4.1 ____ ____
2.05 20.5 ____ ____
43020 4302 ____ ____
• True or false?
4030 ÷ 100 = 43
1.09 × 100 = 190
0.09 × 10 = 0.9
7000 ÷ 1000 = 0.7
• Rounding to nearest tenth
Tick (a) or (b)
(a) 20.07 → 20
(b) 20.07 → 20.1
Rounding to nearest whole number
(a) 20.09 → 21
(b) 20.09 → 20

In-depth investigation: Spiralling Decimals
Take turns to place a decimal number on a spiral number line. Spiralling Decimals from nrich.maths.org.

### Extra Support

Left or Right?
Multiplying numbers with one decimal place by 10 and dividing 2-digit whole numbers by 10

Left, Left or Right, Right?
Understanding place value in numbers with two decimal places;
Beginning to multiply numbers with two decimal places by 100 and divide 3-digit numbers by 100

## Unit 2 Column addition; 2-place decimals (suggested as 2 days)

### Objectives

Unit 2: ID# 5419

National Curriculum
Dec/Fr (ix) (x)

Hamilton Objectives
29. Write decimal numbers as tenths and hundredths.

### Planning and Activities

Day 1 Teaching
Write 4.56 + 2.37 on the board. Ask children to round each number to the nearest whole and add to estimate the total. Demonstrate, using expanded and compact addition, carefully talking through adding 0.07 and 0.06. Ask children to use expanded addition or compact addition to work out other calculations.
Group Activities
Use the ‘Four of the best’ in-depth problem-solving investigation below as today’s group activity.
Or, use these activities:
-- Use expanded and compact layouts to add pairs of numbers with one, then two decimal places.
-- Identify missing digits in additions of 3-digit numbers with two decimal places.

Day 2 Teaching
Show the table of shot put results (see resources). Explain that the total of the shot put throws was used to find the winner. Children estimate who won, and then add two and three decimal numbers to find out.
Group Activities
-- Explore and investigate column addition of 2-place decimals.

### You Will Need

• Whiteboards and pens
• ‘Adding decimals’ sheet (see resources)
• Sticky notes
• ‘Shot put results’ (see resources)
• Number cards 1–9

### Mental/Oral Maths Starters

Day 1
Place numbers with two decimal places on a line (pre-requisite skills)

Suggested for Day 2
24-hour clock (simmering skills)

### Worksheets

Day 1
Written addition of numbers with one then two decimal places.

Day 2
Add two lengths with two decimal places.
Add three lengths with two decimal places.

### Mastery: Reasoning and Problem-Solving

• Sometimes/ Always/ Never… ‘If you add two 2-place decimal numbers, the answer also has two decimal places.’
• Write the missing digits:
4.9☐ + ☐.78 = 8.☐6
• Ali’s homework might need correcting…
Correct any wrong answers and explain what he did wrong.
a) 2.75 + 5.95 = 7.60
b) 3.4.2 + 5.57 = 8.99
c) 4.83 + 1.93 = 5.76
d) 2.47 + 68.5 = 93.2

In-depth Investigation: Four of the best
Children use an incomplete magic square to explore patterns in the addition of four decimal numbers.

### Extra Support

Dancing Decimals
Locating tenths on a 0-3 number line.

## Unit 3 Subtract decimal numbers, e.g. money (suggested as 3 days)

### Objectives

Subtract decimal numbers including money
Unit 3: ID# 5431

National Curriculum
Dec/Fr (vii) (x)

Hamilton Objectives
32. Subtract 1- and 2-place decimal numbers by counting up: 6.2 – 3.5, 13.1 – 9.45.

### Planning and Activities

Day 1 Teaching
Write 98 – 21, 46 – 19, 58 – 32, 74 – 6 and 63 – 57 on a flipchart. How do we solve 98 – 21? Subtract 20, then 1. So how do we solve 9.8 – 2.1? Through discussion, establish that we first − 2, then − 0.1. Model how we can use closely-related counting back strategies to solve the other decimal calculations: 4.6 – 1.9, 5.8 – 3.2, 7.4 – 0.6. Note that Frog is sometimes best, e.g. 6.3 – 5.7.
Group Activities
-- Choose and use an appropriate and efficient method for subtraction.

Day 2 Teaching
Display priced items on the board (see resources). Discuss how much change we would have from £100 to buy a chosen item. Model counting up, using Frog, being sure to distinguish a hop which is pence (to the next pound) and a hop which is pounds. Choose another item and repeat. Calculate a total of two items, then the change from £100.
Group Activities
-- Find money totals and change from £100 (or £50).

Day 3 Teaching
Draw a diagram on the board showing differences between amounts. Use Frog to find which pairs of amounts have which differences. Ensure, when counting up, that children are clear that Frog hops to the next pound first, and this hop is in pence.
Group Activities
Use the ‘Pence and pounds reversed’ in-depth problem-solving investigation below as today’s group activity.
Or, use this activity:
-- Explore money differences using Frog.

### You Will Need

• Eight blank cards
• Two large pieces of paper
• 0–9 dice
• ‘Room makeover’ (see resources)
• Number cards 4–9
• Loose pieces of paper

### Mental/Oral Maths Starters

Day 1
Add to the next whole number from a 1-place decimal number (pre-requisite skills)

Suggested for Day 2
Mental division, answer as fractions (simmering skills)

Suggested for Day 3
Find intervals using 24-hour clock (simmering skills)

### Worksheets

Day 1
Choose whether to count back or count up (Frog) to work out answers to subtractions of numbers with one decimal place.

Day 2
Find the change from £50 and £100, then find totals and the change from £100.

Day 3
Estimate, then find the difference between amounts of money.

### Mastery: Reasoning and Problem-Solving

• Kyla received £7.29 change from a £20 note. How much did she spend?
• Write the missing number in each of the bar models:
Diagram 1

 6.4 2.7 ?

Diagram 2

 9.2 ? 3.5
• Has the shopkeeper given the correct change?
1. Item bought: £13.45
Paid with: £50
Change given: £36.55
2. Item bought: £64.79
Paid with: £100
Change given: £45.31
• Write the missing digits:
£75 – £24.☐6 = £☐.14
• Write two amounts with a difference of £34.76.
The larger amount has 23p.

In-depth investigation: Pence and Pounds Reversed
Children find patterns in the differences when pounds and pence are reversed.

### Extra Support

Change Challenge
Using counting up (Frog) to calculate change from £50

## Unit 4 x/÷ by 10, 100, 1000; rounding decimals (suggested as 2 days)

### Objectives

Multiply/divide by 10, 100, 1000; rounding decimal numbers
Unit 4: ID# 5437

National Curriculum
Dec/Fr (vii) (viii) (ix)

Hamilton Objectives
19. Understand the effect of multiplying/dividing by 10, 100, 1000, including 1- and 2-place decimal answers.
29. Write decimal numbers as tenths, hundredths, thousandths, e.g. 0.71 as 71/100, 0.327 as 327/1000; relate thousandths to tenths and hundredths.
30. Locate 2-place decimal numbers on a line; round them to the nearest tenth or whole number.

### Planning and Activities

Day 1 Teaching
Use an IWB calculator to show the effect of multiplying and dividing by 10 and 100. Use place-value cards (arrow cards) or numbers on the ITP Moving digits to show what happens to each digit when you multiply and divide by 10, 100 or 1000.
Group Activities
-- Investigate routes through a grid (× and ÷ by 10, 100 or 1000) with a range of outcomes.

Day 2 Teaching
Display a 3–5 line marked in tenths (see resources). Mark 3.45. Agree how to round this to the nearest tenth. Then show how to round it to nearest whole number. Ask other children to mark numbers with two decimal places on the line. Children round them to the nearest whole, then tenth.
Group Activities
-- Play games to explore positioning and rounding of 2-place decimals.

### You Will Need

• ITP: Moving digits
• Whiteboard and pens
• IWB calculator
• Multiplying and dividing by 10 and 100 grid (see resources)
• Place value grid (see resources)
• Number line 3–5 marked in tenths (see resources)
• Number line 0–1 marked in tenths (see resources)
• Small pieces of paper and envelopes
• 0–9 dice

### Mental/Oral Maths Starters

Day 1
Place value in numbers with two decimal places (pre-requisite skills)
Suggested for Day 2
Place 6-digit numbers on a number line (simmering skills)
Or
Decimal place value addition and subtraction (simmering skills)

### Worksheets

Day 1
Multiply and divide by 10, 100 and 1000. Answers have up to two decimal places and up to five digits.

Day 2
Place numbers with two decimal places on a 0–1 line.
Round them to the nearest tenth and whole.

### Mastery: Reasoning and Problem-Solving

• Fill the empty boxes:
0.15 = 1.5 ☐ 10
5209 = ☐ × 100
☐ ÷ 100 = 4.7
10.08 = ☐ ÷ 1000
• Think of a number that gains a digit when you divide it by 100.
• True or False?
When you divide a 4-digit number by 100, you end up with a 2-digit number.
• What number am I?
A
(i) I round to 5.6 as the nearest tenth.
(ii) I round to 6 as the nearest whole number.
(iii) My digital root is 6.
B
(i) I round to 3.5 as the nearest tenth.
(ii) I round to 3 as the nearest whole number.
(iii) My digits are consecutive.
• Sam wrote:
3.49 rounds to 4 as the nearest whole number because 3.49 rounds to 3.5 as the nearest tenth, and 3.5 rounds up to 4 as the nearest whole number.
Explain why his reasoning is incorrect.

This unit has no separate in-depth investigation.

### Extra Support

Mark and Round
Placing numbers with one decimal place on a number line; Rounding numbers with one decimal place to the nearest whole number.