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
Homeschool worksheets are far more than busy work. They are an important part of making sure that the concepts you teach in your home school stick with your child. Just make sure you have a good source for providing the worksheets, and that they're the right ones for your kid or kids.
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.