Section 2-2 Problem Solving Using Estimation Strategies Page 54 in your book

Section 2-2 Why do you estimate an answer before you calculate a problem?

Why? So you know your answer is reasonable or not!!

Example I want to buy a grilled cheese sandwich ( 1.89) and a frozen yogurt (1.49). What is the estimated amount? _________ I have $3.00, do I have enough? ________

Different ways to round 1. Round to the nearest ½ dollar. 2. Fount-end estimation.

Round to ½ dollar Example: Add and becomes _______ 1.46 becomes ________ ADD: _________

Example 1. Example: Add and becomes becomes 1.50 ADD: 11.50

Example 2: you do this example in your head. Add $9.82 and $1.76 Answer: _______

Example 2 Add $9.82 and $1.76 Answer: $12.00

Rounding using front-end estimation Step 1: Look at the front numbers (the whole numbers) and add them. Step 2: Look at the end numbers (decimal numbers) and estimate the total amount to the whole number. Step 3: Write the Answer

Example 1 Estimate the cost of a slice of pizza (1.45) and yogurt (1.39) Step 1: Add the front numbers they are ________= _____ Step 2: Add the estimate the end #’ers to the nearest whole number ________ Step 3: Answer ___________

Example 2 Do this one in your head 3.20 and 1.87 Front _____ End _____ Answer _____

Example 2 Do this one in your head 3.20 and 1.87 Front End Approx 1 Answer so

Estimation technique called clustering Estimate the sum: = ____ Estimate each to the same decimal # in this case 2.5 So 2.5 x 5 = 12.5

Another example of clustering Estimate What number could these all be?? So ___ x ____ = _____

Vocabulary word Compatible numbers: When you estimate quotients using numbers that are east to divide mentally. Example: divided by 7.95 Estimate becomes _______ 7.95 becomes ________ Estimated answer ______

Review Today you learned: Why you use estimation strategies You learned to estimate by ½ dollar, front- end, and by clustering. You learned the vocabulary word: compatible numbers.

Assignment Worksheet