# Maths Year 2 Summer Addition and Subtraction

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

## Unit 1 Add by partitioning or counting on (suggested as 2 days)

### Planning and Activities

Day 1 Teaching
Children make 24 and 32 using place value cards. Model this process using Place value ITP. Demonstrate how to add the two 10s and the two 1s and then recombine: 30 + 20 = 50 and 2 + 4 = 6. Total = 56. Also show how to count on in 10s and 1s (start at 32; add 20 then 4): 32..42..52..53..54..55..56. Which strategy do you prefer? Ask children to work out 73 + 21, 52 + 37, 54 + 26. Model 47 + 35 using partitioning, to show what happens when the ones add to more than ten.
Group Activities
-- Add two 2-digit numbers from number cards, noting methods used.
-- Add two 2-digit numbers from dice, explaining reasons for methods used.

Day 2 Teaching
Remind children of the two methods they used in Day 1 for adding: partitioning and counting on. Practise adding two 2-digit numbers, allowing children to choose their preferred method. Ask two children using different methods to explain why they used the method they chose.
Group Activities
Use the in-depth problem-solving investigation ‘Diagonal hundreds’ as today’s group activity.
Or, use these activities:
-- Add two 2-digit numbers from spinners, choosing appropriate methods.
-- Add two 2-digit numbers, suggesting the method to be used and devising ‘top tips’ for method selection.

### You Will Need

• Place value cards
• Place value ITP
• Whiteboards and pens
• 2-digit number cards
• 10 second timer
• Calculators
• Customised dice (see activity for details)
• Top Marks spinners from www.topmarks.co.uk
• Mobile internet access devices

### Mental/Oral Maths Starters

Day 1
Add a 1-digit number to a 2-digit number (pre-requisite skills)

Day 2
Subtract a 1-digit number from a 2-digit number (pre-requisite skills)

### Worksheets

Day 1
Select appropriate methods to add two 2-digit numbers.

Day 2
Select appropriate methods to add two 2-digit numbers for more challenging calculations.

### Mastery: Reasoning and Problem-Solving

Look at this bar diagram. Work out the value of the missing number:

 ? 32 64
• Explain why it might help to change the order of this addition before we try to find the answer.
15 + 62 = ☐
• Would you use counting on or partitioning to work out these additions? Why? Find the answers.
35 + 57
77 + 22
84 + 6
• Sam had some stickers. His sister takes 22 and he gives his friend 45. He has none left. How many did he start with?

In-depth Investigation: Diagonal hundreds
Children use trial and improvement to place numbers in a grid to give a pair of diagonals whose sum is equal to 100.

### Extra Support

Square Sums
Adding ‘friendly’ 2-digit numbers using partitioning (1s<10)

## Unit 2 Choose strategies to subtract (suggested as 3 days)

### Planning and Activities

Day 1 Teaching
Start with 87p and say you will spend 33p. Model marking these numbers on a 0p to £1 number line, and showing how we can count back three 10ps and then hop back another three 1ps to land on 54p.
Now spend another 38p, this time showing how we can count up using Frog to hop up the number line from the smaller to the bigger number.
Group Activities
-- Find the difference between two numbers involving money, using different methods.
-- Find the difference between two 2-digit number cards, explaining reasons for choosing methods used.

Day 2 Teaching
Remind children of the two methods they have explored for subtracting. Generate a 2-digit – 2-digit subtraction and model using both methods. Repeat. Discuss which methods the children used for their calculations and why. Which do you think was more efficient in this example…?
Group Activities
-- Find the difference between a pair of 2-digit numbers, choosing an appropriate method.
-- Find the difference between a pair of 2-digit numbers, suggesting the method to be used and devising ‘top tips’ for method selection.

Day 3 Teaching
Display three word problems (see resources). Read each. Agree whether we need to add or subtract. Give children time to work out answers before working through as a class. Refer to the Top Tips notes (made previously) to help decide which addition or subtraction strategy to use.
Group Activities
Use the ‘problem-writing’ group activity from today to apply skills from across this unit.
Or, use these activities:
-- Solve addition and subtraction word problems.
-- Write addition and subtraction word problems.

### You Will Need

• 0 to £1 penny number line (see resources)
• Resource sheets for tables A, B and C (see resources)
• 1-100 grids
• 2-digit number cards, timers and calculators
• Top marks spinners from www.topmarks.co.uk
• Internet access and digital devices
• Additional activity sheets (see resources)
• Whiteboards and pens
• Priced items

### Mental/Oral Maths Starters

Day 1
Add to the next 10 (pre-requisite skills)

Day 2
Bonds to 10 (pre-requisite skills)

Day 3
Add 1-digit numbers to 2-digit numbers (pre-requisite skills)

### Worksheets

Day 1
Solve subtraction with money using various methods.

Day 2
Solve subtractions then sort them according to the methods used.

Day 3
Complete and create addition and subtraction word problems.

### Mastery: Reasoning and Problem-Solving

• Four purses contain the following amounts: 37p, 48p, 25p, 53p.
Take 23p out of each purse. How much is left in each?
• Choose whether to use Frog to count up or whether to count back. Explain why you chose that method:
62 – 38
66 – 33
75 – 6
83 – 79
84 – 12
24 – 18
• Calculate the missing number in each bar model diagram. Diagram 1:
 64 ? 57

Diagram 2:

 79 31 ?

In-depth Investigation
Use and apply skills from this unit by completing the ‘Problem-writing’ group activity from Day 3.

### Extra Support

Pocket Money
Subtracting 11, 12, 13 from 2-digit numbers by counting back