MathWorld provides a detailed definition of addition.

Practice subtracting 1 or 10 from a 2-digit number (no regrouping). Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

2000 basic subtraction worksheets are available at this web site. They can be printed and used for a variety of practice purposes. Some helpful hints are included to avoid mindless practice that could quickly become counter productive.

Practice several different levels of difficulty of addition problems from single digit all the way up to 3 digit with regrouping. You can also choose single digit addition with negative numbers. When you are finished you can print your...

Lizard Point provides practice using several difficulty levels of multiplication problems. It has single digit times single digit, single digit times two digit, two digit times two digit, and three digit times three digit. When you are...

2000 basic multiplication worksheets are available at this web site. They can be printed and used for a variety of practice purposes. Some helpful hints are included to avoid mindless practice that could quickly become counter productive.

On this one page website sharpen your logic and addition facts skills while working on this challenge. The solution is available to double check your solution.

On this one page website sharpen your logic and addition fact skills while working on this challenge. The solution is available to double check your solution.

On this one page website sharpen your logic and addition facts skills while working on this challenge. The solution is available to double check your solution.

In this interactive website put twenty multiplication problems in order according to the increasing value of their products.

This website for young children gives them practice adding sums to 10. Problems are presented as teddy bears to add up with the corresponding digits that represent the problem symbolically.