Front-End Estimation Study Guide

What is Front-End Estimation?

How to Use Front-End Estimation for Addition

1. Look at the leftmost digit of each number.
2. Add these digits together to get the estimated sum.
3. Add zeros to the right of the estimated sum to match the place value of the original numbers.

Example:

1. Look at the leftmost digits: 3 and 2.
2. Add these together: 3 + 2 = 5.
3. Add zeros to the right: 5000.
4. So, the estimated sum is 5000.

How to Use Front-End Estimation for Subtraction

1. Look at the leftmost digit of the minuend (first number).
2. Subtract the leftmost digit of the subtrahend (second number) from the leftmost digit of the minuend.
3. Add zeros to the right of the estimated difference to match the place value of the original numbers.

Example:

1. Look at the leftmost digits: 7 and 2.
2. Subtract: 7 - 2 = 5.
3. Add zeros to the right: 5000.
4. So, the estimated difference is 5000.

Practice Questions

1. Estimate the sum of 4567 + 1234 using front-end estimation.
2. Estimate the difference of 8901 - 2345 using front-end estimation.