This lesson plan has students exploring was to add and subtract numbers with multi-digits and place value.

At this site from Lizard Point Consulting, you can practice several different levels of difficulty of subtraction problems that use 1-digit numbers all the way up to 3-digit number subtraction problems that require regrouping. You can...

Read through this explanation of how to add three digit numbers. Use the online game to practice this skill. The game will keep running totals of your correct and incorrect answers. It will also show you a percent score of the correct...