Another problem with almost all worksheets is that they don't prevent incorrect answers. Self_checking worksheets just let the student know they did something wrong__after the fact. I am a firm believer in the concept that, if at all possible, learning should be structured in small chunks in such a way that there is very little possibility for error. Worksheets often allow for mistakes to be made and then to be repeated many times. A mistake that gets practiced is extremely difficult to correct. This especially happens when worksheets are used as time fillers or baby sitters and the work isn't really being supervised.
In this modern, technology lead world it is easy to overlook the importance of basic mathematics and mental arithmetic. When every mobile phone has a calculator built in, and every website automatically adds up your shopping cart, who needs to add up in their head? The fact is that mathematics is a vital life skill and as adults we know it is something we use every day in our adult lives. We know that it is essential that we teach our children how to do maths from a young age, but sometimes it is easy to overlook the simple steps we can take at home. We can all remember learning our times_tables at school _ one times one is one, two times two is four, and so on _ but there was a reason why we learnt this way, because it works. But it's not just about learning the times tables in sequence through repetition, it's important to get kids practicing with varying levels of multiplication problem. Working through problems and then checking the answers afterwards is a simple way to practice multiplying numbers.