Lesson 3-1 Rounding and Estimating

Writing Decimals Express using words. And represents the decimal point Write two and three hundredths

Some real life problems require only an estimate while others require an exact answer. – A headline noting the number of people living in China. – The amount of money a baby sitter charges per hour. – The width of a window screen. – The distance from Earth to the moon. – The hours at football practice in one month. – The number of tickets sold for a play.

You can round decimals when you don’t need exact values. When rounding if the number to the right is 5 or greater---round up When the number to the right is less than 5 do not change the number

Round to the nearest hundredth Round to the nearest tenth

≈ means approximately equal to 126 ≈ 130 One way to estimate is to round all numbers to the same place –

Front end estimating – add the front-end digits. Round to estimate the sum of the remaining digits. Then combine estimates. Carrots cost $2.71, peppers cost $1.73 and broccoli costs $1.10. Estimate the total cost of the vegetables

You can use clustering to estimate the sum of several numbers that are close to the same value