At my DS6 school, they use 50 questions in under 3 minutes, and all must be correct before they move on.
Addition first using numbers that add to no more then 20, then subtraction, then mixed. Theres about 2 sheets for each. Then the move to multiplacation, using 2-12 one at a time then mixed.
Afte this I don't know. They do other math in school these arejust work sheets