# Key Stage 2, Maths, Extending calculation strategies and additive reasoning

Lesson 1

## Adjusting addends

Lesson 2

## Same sum' with larger numbers

Lesson 3

## Same sum' with decimals

Lesson 4

## Balancing equations using the 'same sum' strategy

Lesson 5

## Balancing equations using compensation

Lesson 6

## Balancing equations: Does the order of addends matter?

Lesson 7

## Increasing an addend

Lesson 8

## Decreasing an addend

Lesson 9

## Solve calculations mentally by relating them to known facts

Lesson 10

## Find an unknown addend

Lesson 11

## Introduction to same difference

Lesson 12

## Same difference in context

Lesson 13

## Use the Language of Minuend, Subtrahend, and Difference

Lesson 14

## Transform calculations using the same difference

Lesson 15

## Practice: Transforming Calculations to Make Them Easier to Solve Mentally

Lesson 16

## Transform a subtraction calculation to make the written algorithm easier to apply

Lesson 17

## Practice: 'Same Difference' in Different Contexts

Lesson 18

## Balancing equations to find unknown values

Lesson 19

## Explore how the difference changes when only the Minuend is changed

Lesson 20

## Apply the generalisation about how the minuend and difference change to solve problems

Lesson 21

## Explore how the generalisation can be used as a mental calculation strategy using Known facts

Lesson 22

## Thinking flexibly

Lesson 23

## Comparing Strategies

Lesson 24

## The more we subtract, the less we are left with. The less we subtract...

Lesson 25

## Contexts where the Minuend is Kept the Same, and the Subtrahend Increases

Lesson 26

## Contexts where the minuend is kept the same, and the Subtrahend decreases

Lesson 27

## Further practice to reason about how the change in the subtrahend changes the difference

Lesson 28

## Explore problems in which the new difference must be found

Lesson 29

## Balance Equations Where the Compensation Property of Same Sum Cannot Efficiently be Applied

Lesson 30