Obviously the goal with mental arithmetic is to be fast and accurate, but I noticed when my own son was tackling division practice, he desperately wanted to be right rather than fast.
The lesson for me was that to build confidence, as easier set of whole number division questions was needed, which is why today you see the Division starter.
The parent/mentor role becomes huge because the guidance to do practice requires a lot of patience. So far what I’ve seen as effective are these techniques.
– Do a little bit every day. Enforce 15 minutes then encourage more
– Don’t give the answer unless asked by the person practicing
– Show them how you do it
– Do the practice sessions yourself while they watch
– Do not fear if they don’t seem to retain the answers swiftly
Persistence first. Speed second.