Wednesday, February 27, 2013

Subtraction Algorithms

In class we have learned to different algorithms(procedures) for solving multi-digit subtraction problems.

Remember "Counting Up" turns the subtraction problem into an addition problem. This algorithm can help you build your mental math skills.

"Trade-first" is the traditional algorithm for subtraction. It can be more friendly and efficient with larger numbers.

Click on the the link below the picture to remind yourself how to use the "Counting Up" and "Trade-first" Algorithms.