Another aid that can help children practise subtraction is the number strip. TGS can be used to improve their ability to count backwards. For example, subtracting 4 from 9 means to first count 9 steps ahead, and then 4 steps backwards, and see where you are.

Figure: Using a number strip to show 9 - 4.

Once the process involved in subtraction is clear to the children, you could introduce the symbol for subtraction to them. Again, they would need to use the term 'minus' and the symbol '-' a great deal before they could be expected to be familiar with them.

As seen already, subtraction is easy for the child when objects are used. She removes the required number of objects and counts the remaining ones. Or she may draw several strokes and cross out the required number she may count backwards on a number strip too. But, if subtraction is introduced without any of these devices, she is likely to have trouble in even solving problems like 'subtract 8 from 13'.