Save Money : It's easy to see how free worksheets can save you money. If you want, you can skip buying math books and just use worksheets that you get for free on the internet. All you need to do is use a "scope and sequence" book that tells you what your child needs to be doing in math by age and grade. This book is essential when you homeschool.
Save Time : Free worksheets not only save you money, they can also save you time. If you decide that it is best for your child to do worksheets especially tailored for his needs, by doing a little research for printable math worksheets found online, you don't have to make the worksheets yourself. This can save a lot of time. Worksheets aren't that difficult to make, but it can be time consuming.
Subtract 1-, 2-, or 3-digit numbers from 3- and 4-digit number with/without renaming
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.