Written Calculations: Subtraction

Subtraction Vocabulary

This page shows how we teach addition at Nettlestone. It is important to understand that children do not progress on to these formal written methods until they can add or subtract any pair of 2 digit numbers, and have used informal paper and pencil methods of subtraction as detailed on the mathematics home page.

Building on mental strategies, the expanded method of subtraction is taught:

The numbers are partitioned:

68 -24

60 8

-20 4

40 4

then recombined 40 + 4 to give the answer 44

We can’t take 7 from 2 so we will exchange a ‘ten’ for ‘ten ones’ to give us 12. Ensure child understands that the number 362 has just been redistributed – 300 + 50 + 12 = 362

Leading to:

Known as the decomposition method