Posted by Peter on 17th February 2010

Resource of the Week: subtraction

count-up-crossing-thousandsThere are many occasions when a 4-digit subtraction can be done ‘in your head’. These questions, suitable for Year 5, are examples of this. They all involve numbers which are just over and just under a whole thousand.

For example: 3003 – 2994

Probably the easiest way to do this mentally is to count on 7 from 2993 to make 3000 and then count on, or add, the extra 4, making 11.

This is much easier than doing the question on paper, with lots of ‘borrowing’ and carrying, crossing out etc!

We have a growing number of pages on mental subtraction including this:

Count up crossing thousands

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