Standard written methods of subtraction worksheets from mathsblog.co.uk
Written methods of subtraction often cause problems for children and it is important to state that a good mental knowledge of numbers is essential if written methods are going to be grasped successfully.
In the UK the standard method of subtraction is often known as decomposition. It should be used when numbers are too large or too awkward to subtract mentally. Remember: mental methods should be the first resort!
The first page of the link shows how the decomposition method works, and is probably the one you learnt at school, although there are other, equally valid methods of subtraction.