Estimation and Determining Reasonableness of a Solution TEKS 6.2D Lesson 5 (2 nd 6 Weeks)

Estimation Round the numbers in the problem before any arithmetic is done. Then solve the problem using the rounded numbers. The estimate tells about how big or small the exact answer should be.

Estimation can help you decide whether the exact answer is reasonable. Estimates can also be made when an exact answer to a problem is not needed.

EX: The sticker on Ms. Land’s new car shows that its average gas mileage is 28 miles per gallon of gas. Ms. Land drives about 67 miles each workday. About how much gas will Ms. Land use the 21 days of driving to work this month?

67 miles per day x 21 days = number of miles Ms. Land drives Round 67 to ____ and round 21 to _____. ______ x ______ = _________ Mrs. Land drives about _________ miles in 21 days

Estimate how much gas Ms. Land will use to drive 1400 miles miles ÷ 28 miles per gallon = number of gallons Round 28 to _____ ÷ 30 = ________ which rounds to _______ Ms. Land uses about ______gallons of gas in 21 workdays