What do I do when my kid has a hard time subtracting?

First, I would buy some unifix cubes. They stack into groups of ten and can be taken apart again to show regrouping/borrowing/carrying. This physical piece is very important for most learners.

Your child can practice putting the cubes into groups of ten like sticks and then doing math they already know and feel confident with. Example 10+7, then 14+7, then 26+21, then 26+25…

Then once they are used to these, I would introduce a game like Zeus on the Loose*. This game practices adding 0–100. They could practice using the unifix cubes to add. Occasionally you subtract by 10.

After doing that 7–10 times, you could try playing Zeus on the Loose backwards. Instead of starting at 0 and winning when you get to 100, you start at 100 and win at 0. Now the whole game is subtracting. Do not try to introduce the written subtraction; focus on the unifix cubes for weeks.

Then later play Zeus on the Loose forwards (0 to 100) and write down the addition problems on paper/whiteboard. Do that several times (3–10).

Then try Zeus on the Loose backwards and writing down the subtraction problems for weeks.

*We are not sponsored by this game in any way.