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

Maths

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

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

Which of these is the correct equation represented by this bar model?

Which of these is the correct equation represented by this number line?

What is the difference between the two values shown in the bar model?

What is the difference between the two values shown?

Which of the pairs of numbers have the greatest difference?

Which of these subtraction expressions can be more efficiently solved by finding the difference?

What is the missing part in this bar model?

Match the numbers so that they make a pair with a sum of 100.

Use a find the difference strategy to calculate: 54 − 47 = {{ }}

Use a partitioning strategy to find the sum of 135 and 270

Starter Quiz