Borrowing, the tricky skill
Subtraction with regrouping often takes longer to settle than carrying does. In this set of 20 problems, every one needs a ten to be traded into ones. Children get steady practice in the step they find hardest, with no easy problems to pad the page.
The mistake to look for
The most common error is subtracting the smaller digit from the larger whichever way round they appear, so 52 – 27 becomes 35. If you see that pattern, go back to base-ten blocks. Show 52 as five tens and two ones, then ask whether seven ones can be taken from only two. Trading a ten for ten ones makes the reason for borrowing clear.
Check with Santa's list
Santa checks his list twice, and so can your class. Ask students to add their answer to the bottom number, which should give the top number. Anyone whose check matches earns a check mark on a class "nice list" for math.
Getting ready for winter break
Press "New sheet" to make a second page with new problems. Send it home as optional holiday practice so the skill stays fresh for January.