They can:

1)   Do it in their head getting either an exact answer or an estimate.

2)   Do it on paper computing the exact answer. (See Algorithms)

3)   Use a calculator to perform the computation.

When should students use a calculator?

My philosophy is that calculators should be used only when the task is too tedious to perform in the other manners.  Most computation can be solved using either mental math or paper and pencil. 

A good rule of thumb is to ask yourself how would you do this task?

If you would use a calculator for this task then it is probably appropriate for your child to do so also.  The only exception to this rule is when the intent of the activity is to test the student’s ability to compute without a calculator.

One game we play to try to make the point that mental math is often better than a calculator is called “Beat the Calculator.”

It is a game for three people.  One person is the caller, the second is the brain, and the third is the calculator.  The caller calls out a basic fact using any of the four operations that is appropriate for the players.  – (See Expectations).  The Brain and the Calculator race to be the first to solve the equation.  The only rule is the calculator must push all the keys of the equation.  Play until one player wins 10 times then switch roles.

This is a version of a Speed Building Game and should not be used with students that are not conceptually ready.