Times are different these days. Kids are growing up in a world of microwaves, fast food chains, Nintendo, Wifi, iPads, along with a ton of other technical marvels.
In other words, they never memorized their multiplication tables! Many times I have seen a student do poorly due to a weakness in basic math facts they should have learned in third grade.
Subtract 1-, 2-, 3-, 4-, or 5-digit number from a 5-digit number
Solve vertical and horizontal computation problems