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Lesson Menu Five-Minute Check (over Lesson 3–3) Main Idea and Vocabulary Example 1:Use Estimation to Solve Problems Example 2:Use Estimation to Solve Problems Example 3:Use Clustering Example 4:Use Front-End Estimation Concept Summary: Estimation Methods

Main Idea/Vocabulary Estimate sums and differences of decimals. clustering front-end estimation

Example 1 POPULATION The table below shows the population of the American colonies in Estimate the total population of North Carolina and South Carolina. Use Estimation to Solve Problems

Example 1 Use Estimation to Solve Problems Answer: There were about 300 thousand people in North Carolina and South Carolina  rounds to  rounds to 100. Round each number to the nearest hundred for easier adding.

1.A 2.B 3.C 4.D Example 1 The table below shows the population of the American colonies in Estimate the total number of people in Pennsylvania and New Hampshire in A.300 thousand people B.400 thousand people C.500 thousand people D.600 thousand people

Example 2 POPULATION The table below shows the population of the American colonies in Estimate how many more people lived in Rhode Island than in Georgia in Use Estimation to Solve Problems

Example 2 Use Estimation to Solve Problems Answer: There were about 40 thousand more people in Rhode Island than in Georgia  rounds to –23.4  – rounds to 20.

1.A 2.B 3.C 4.D Example 2 The table below shows the population of the American colonies in Estimate how many more people were in Massachusetts than in Connecticut. A.50 thousand people B.60 thousand people C.70 thousand people D.80 thousand people

Example 3 Sid feeds a vitamin-water solution to his guinea pigs. The table shows the amount of solution the guinea pigs drank over a period of four days this week. Which is the closest to the total amount of solution the guinea pigs drank? A.40 ounces B.60 ounces C.80 ounces D.100 ounces Use Clustering

Read the Item The addends are clustered around 20. Round each decimal to 20. Example → → → → Use Clustering

Example 3 Solve the Item Multiplication is repeated addition. So, a good estimate is 4 × 20, or 80. Answer:C Use Clustering

1.A 2.B 3.C 4.D Example 3 During the month of February, Jonathon spent $14.78 on gasoline the first week, $15.35 on gasoline during the second week, $15.24 on gasoline during the third week, and $14.97 on gasoline during the fourth week. Which is the closest to the total amount Jonathon spent on gasoline during February? A.$35 B.$50 C.$60 D.$100

Example 4 Estimate using front-end estimation. Use Front-End Estimation 14.8   +50.0Add the front digits. Answer: Using front-end estimation, is about 60.0.

1.A 2.B 3.C 4.D Example 4 Estimate using front-end estimation. A.90.0 B C D.120.0

Concept Summary Estimation Methods Estimate by rounding each decimal to the nearest whole number that is easy for you to add or subtract mentally. Estimate by rounding a group of close addends to the same number before adding. Estimate by adding or subtracting the values of the digits in the front place. Rounding Clustering Front-End Estimation

End of the Lesson

Resources Five-Minute Check (over Lesson 3–3) Image Bank Math Tools Modeling Decimals Dividing Decimals Modeling Decimals

1.A 2.B 3.C 4.D Five Minute Check 1 Round to the nearest tenth. A.8.4 B.8.43 C.8.44 D.8.5 (over Lesson 3-3)

1.A 2.B 3.C 4.D Five Minute Check 2 Round to the nearest thousandth. A.9.65 B C D.9.64 (over Lesson 3-3)

1.A 2.B 3.C 4.D Five Minute Check 3 Round to the nearest hundredth. A.1.3 B.1.26 C.1.25 D.1.2 (over Lesson 3-3)

1.A 2.B 3.C 4.D Five Minute Check 4 Round to the nearest ten-thousandth. A B C D (over Lesson 3-3)

1.A 2.B 3.C 4.D Five Minute Check 5 Round to the nearest hundredth. A.8.2 B.8.23 C.8.24 D.8.3 (over Lesson 3-3)

1.A 2.B 3.C 4.D Five Minute Check 5 The average retail price of gasoline in Texas during the week of March 13, 2006 was $2.283 per gallon. Round this to the nearest cent. A.$2.30 B.$2.29 C.$2.28 D.$2.27 (over Lesson 3-3)

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