For this reason, attractive, well-illustrated worksheets with something to do will make learning fun for them. What's more, completing your worksheet will give the child a tremendous sense of fulfillment.
There are other sources for worksheets also. You can find many public schools and private schools which will provide free worksheets for you if you buy textbooks from the school.
Subtract 1-, 2-, or 3-digit numbers from 3- and 4-digit number with/without renaming
As a middle-school math teacher, I have seen many students who do understand abstract concepts, and even enjoy learning about things like Pi and the Pythagorean Theorem, but who appear to be unable to do so due to a weak grasp of math fundamentals.