# Manipulating the additive relationship and securing mental calculation

Unit 4 – 4 weeks

Primary KS2 Year 3
Curriculum

The PowerPoint file contains slides you can use in the classroom to support each of the learning outcomes for this unit, listed below.

The slides are comprehensively linked to associated pedagogical guidance in theĀ NCETM Primary Mastery Professional Development materials. There are also links to the ready-to-progress criteria detailed in theĀ DfE Primary Mathematics Guidance 2020.

### Learning outcomes

# Title
1 Pupils add two 3-digit numbers using partitioning
3 Pupils add a pair of 2- or 3-digit numbers using redistribution
4 Pupils subtract a pair of 2- or 3-digit numbers, bridging a multiple of 10, using partitioning
5 Pupils subtract a pair of 2-digit numbers, crossing a ten or hundreds boundary, by finding the difference between them
6 Pupils subtract a pair of three-digit multiples of 10 within 1000 by finding the difference between them
7 Pupils evaluate the efficiency of strategies for subtracting from a 3-digit number
8 Pupils explain why the order of addition and subtraction steps in a multi-step problem can be chosen
9 Pupils accurately and efficiently solve multi-step addition and subtraction problems
10 Pupils understand and can explain that both addition and subtraction equations can be used to describe the same additive relationship (2-digit numbers)
11 Pupils understand and can explain that both addition and subtraction equations can be used to describe the same additive relationship (3-digit numbers)
12 Pupils use knowledge of the additive relationship to rearrange equations
13 Pupils use knowledge of the additive relationship to identify what is known and what is unknown in an equation
14 Pupils use knowledge of the additive relationship to rearrange equations before solving

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