There are a number of different ways in which subtraction problems can be phrased including terms such as ‘Take from’ and ‘How many more’. This maths worksheet looks at some of them, whilst concentrating on subtracting from 20 using mental methods.
The usual method of mentally subtracting is to ‘add on’. For example 20 – 7.
Add 3 to 7 to make 10 and then add a further 10 to make 20. Answer 3 + 10 which is 13.
Or, the ten could be added first to make 17 and then count on to 20.
Either way is equally good.
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