ESTIMATION What Is Estimation? When you make an estimate, you are making a guess that is approximate. This is often done by rounding. How to Estimate: • When estimating, you will often need to round off the numbers with which you are working. For example: There are 148 gumballs in three jars. If the jars have about the same amount, estimate how many gumballs are in each jar? To solve this problem: o First round 148 to 150. 150 is an easier number to work with when estimating. o Now take 150 and divide it into three parts. Since 50 + 50 + 50 = 150, then there are approximately 50 gumballs in each jar. • When estimating to add or subtract, round each number before adding or subtracting. For example: To estimate the sum of 23 and 17: o First round 23 and 17 to the nearest ten. 23 rounded to the nearest ten is 20 17 rounded to the nearest ten is 20 o Then add 20 and 20 together. 20 + 20 = 40 To estimate the difference between 32 and 14: o First round 32 and 14 to the nearest ten. 32 to the nearest ten is 30 14 to the nearest ten is 10 o Then subtract 10 from 30. 30 – 10 = 20 © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
Try This! Estimate the sum of the following. 24 + 37 = ______ 62 + 19 =______ 31 + 46 = ______ 18 + 48 =______ Estimate the difference of the following. 48 – 31 = ______ 52 – 29 = ______ 88 – 53 = ______ 76 – 20 = ______ © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.