When children are learning how to do the formal written method of multiplication it is a good idea to maintain interest by varying the type of exercise whilst keeping to the correct method. A popular task with those advocating mastery in maths has been to provide the whole calculation but with missing digits. The task is to find the missing digits. This type of question has also cropped up in the KS2 maths SATs over the last few years.
For children to be successful in this they do need to understand the method and if they do make mistakes these pages are also useful for the teacher as they usually show exactly where misunderstandings lie. These types of question are also excellent for white boards and whole class interactions where children can explain their thinking and answers.