# Rounding Decimal Numbers

## Presentation on theme: "Rounding Decimal Numbers"— Presentation transcript:

Rounding Decimal Numbers
Sometimes close enough is good enough!

Molly has \$16 in her pocket
She buys: 3 \$1.89 each 3 \$2.19 each 3 Large French \$ \$1.79 each Does she have enough money?

About how much will it cost to fill up?
Gas costs \$1.79 per gallon I’m running on empty and I have a 20 gallon tank on my truck…… About how much will it cost to fill up?

You have one hour to take a 50 question test.
About how much time can you spend on each question? Close enough is good enough!

The rounding poem Find your number Look right next door
4 or less, just ignore 5 or more add one more!

Rounding Whole Numbers
Round 474 to the closest hundred. 474 Find your number Look right next door Four or less, just ignore Five or more, add one more

474 Rounded to the hundreds becomes 500
Round 474 to the closest 10’s 474 Just ignore - 470

Try These 4,215 394 27 127,591 638

The same rules (and poem) apply! Round to the closest hundredths 4.167 Find your number Look right next door 4.17

Remember If you are asked to round to the nearest tenth…….your answer stops at the tenth place! Example: Round to the closest tenth would be 42.7

Special Case! Rounding a 9
Round to the closes hundredths Since there is a “9” in the hundredths place consider the tenth and hundredths together – 19 – do you leave it at 19 or move it to 20?

Round 4.95 to the closest tenth
Since there is a “9” in the tenth spot consider the ones and tenths together…… should you leave it at 49 or move it to 50? 4.95 rounded to the nearest tenth is 5.0

Try these 4.56 4.6 5.32 5.3 0.98 1.0 Round to hundredths
Round to tenths: 4.56 4.6 18.784 18.78 5.32 5.3 9.46 9.456 10.00 0.98 1.0 9.997

Homework Page 600 Lesson 3-3 at the top of the page 1-20