The sum means the total when the numbers are added together.

Unisiting means treating groups that contain the same number of things as 'ones' or 'units'.

Add two 3-digit numbers using partitioning

Maths

Add two 3-digit numbers using adjusting strategies

Add 2 and 3-digit numbers by redistributing

Choose the most efficient strategy to add two 3-digit numbers

Subtract 2 or 3-digit numbers using partitioning and bridging a multiple of 10

Subtract a pair of 2-digit numbers by finding the difference

Subtract 3-digit multiples of 10 by finding the difference between them

Choose the most efficient strategy to subtract from a 3-digit number

Use addition and subtraction to solve problems involving bar charts, pictograms and tables

Use addition and subtraction to solve problems in different contexts

In this unit pupils will add and subtract two 3-digit numbers using partitioning, adjusting, redistribution and bridging. In the future unit pupils will accurately and efficiently solve multi-step addition and subtraction problems. They will understand and explain how both addition and subtraction equations can be used to describe the same additive relationship.

In the prior unit pupils found pairs of number that composed 100 and positioned 3-digit numbers on a number line and estimated their position on unmarked number lines. They compared and ordered 3 digit numbers. In this unit pupils will add and subtract two 3-digit numbers using partitioning, adjusting, redistribution and bridging

In this unit pupils will add and subtract two 3-digit numbers using partitioning, adjusting, redistribution and bridging.

Informal and mental strategies for adding and subtracting two 3-digit numbers

Which group has a different number of 'units'?

Match the expressions with the most relevant strategy for mental addition.

An addend is a number multiplied by a number.

An addend is a number subtracted from another.

The bucket balance has been filled with marbles and blocks. It is balanced. Which of these most closely represent the equation shown by the bucket balance?

Add two 3-digit numbers using partitioning

Lesson outcome