Mrs. Dempsey
Estimation Rules

Estimation is an important tool in mathematics. 

When you estimate the answer before you solve a lengthy algorithm, you know if your answer looks correct.

Multiplication:

When you estimate multiplication problems, round the number so that the first digit is a number other than zero and make all the other digits zero.

43,738 becomes 40,000               366 becomes 400

Addition & Subtraction:

When you estimate addition and subtraction problems, round all the numbers to the same place value.

4,328 + 294 + 36,831 becomes 4,300 + 300 + 36,800

Division:

When you estimate division problems, round the numbers so that the number you are dividing can be easily divided by the second number.

44,287      becomes    45,000    because 5 goes into 45

            48                                    50