Step 3 Objective

Use known number facts and place value to consolidate mental addition and subtraction.

Examples of what pupils should know and be able to do

Add or subtract three-digit multiples of 10.

Add or subtract a single-digit multiple of 100 to or from a three- or four-digit number, crossing 1000.

Add or subtract a three-digit multiple of 10 to or from a three-digit number, without crossing the hundreds boundary.

Continue to find what to add to a three-digit number to make the next higher multiple of 100.

Find what to add to a decimal with units and tenths to make the next higher whole number.

Find the difference between two numbers lying either side of a multiple of 1000.

Probing questions

Explain how you did this calculation.

Are there other ways that are more efficient?

What if pupils find this a barrier?

Check that pupils are able to add and subtract a pair of two-digit numbers mentally (Step 2).

Continue to focus on getting pupils to explain their methods to each other. Use number lines and encourage pupils to visualise number lines in their heads.