Use a calculator under these situations:
1. When working with very large numbers
2. When working with decimals
3. When solving a difficult graphing or function question.
4. After setting up the problem correctly with your pencil, use your calculator to solve whatever equation, ratio or matrix you have scribbled on the page.
Do not use your calculator as the primary source for solving math problems. It cannot think for you. Use your calculator at the end of the solution not the beginning. Use your calculator to check for arithmetic errors and to confirm what you already know.