3-2 Estimating Decimal Products and Quotients

1. Estimate the productHow do I estimate

the product?Round to the nearest

one7.65 • 3.2

Estimate4.72 • 1.8

17.02 • 3.78

2. Check calculationsHow to check

calculations…Arlene bought 6 yd

of fabric to make a quilt. The fabric cost $6.75/yard. The sales clerk charged Arlene $45.90 before tax. Did the clerk make a mistake?

Round to nearest dollar6.75 ≈ 7

Multiply by how many yards she bought

You buy 8 rolls of film. Each roll costs $4.79. Estimate the cost of the film before tax.

3. Estimate the quotientHow do I estimate

the quotient?Compatible numbers

– numbers that are easy to divide mentallyRound denominator,

then round numerator

A bowling ball has a mass of 5.61 kg. Each bowling pin has a mass of 1.57 kg. How many bowling pins are about equal to the bowling ball in mass? Estimate 5.61 ÷ 1.575.61 ≈ 61.57 ≈ 2

6 ÷ 2 = 3

38 . 9 ÷ 1.79

11.95 ÷ 2.1

3-2 Puzzle Activity

Homework: 3-2 Guided ProblemSolving pg in WB