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Glencoe Math: Course 2, Volume 1

GM

Glencoe Math: Course 2, Volume 1 View details

2. Percent and Estimation

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Exercise 3 Page 115

Start by rounding the percent. Then multiply the rounded percent by 90.

About 18

Practice makes perfect

We want to estimate 21 % of 90. Let's start by rounding the percent. rcl 21 % & ≈ & 20 % Now we multiply 20 % by 90 to get an estimation. First, we write the percent as a fraction.

20 %* 90

▼

Write the percent as a fraction

Write as a fraction

20/100 * 90

a/b=.a /20./.b /20.

20÷ 20/100÷ 20 * 90

Calculate quotient

1/5 * 90

MoveRightFacToNumOne

1/b* a = a/b

90/5

Calculate quotient

18

We found that 21 % of 90 is about 18.

Subchapter links

Guided Practice p.114

Independent Practice p.115-116

H.O.T. Problems p.116

Standardized Test Practice p.116-118

Extra Practice p.117

Common Core Review p.118