Rounding Decimals

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Rounding decimals

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Rounding Decimal Numbers : 

Rounding Decimal Numbers Sometimes close enough is good enough!

Slide 2: 

Molly has $16 in her pocket She buys: 3 hotdogs @ $1.89 each 3 milkshakes @ $2.19 each 3 Large French fries @ $ $1.79 each Does she have enough money? Why do we need to know how to round decimals?

Slide 3: 

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. : 

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 : 

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

Rounding Whole Numbers : 

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

Slide 7: 

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

Try These : 

Try These 4,215 394 279 127,591 638

Are You Right? : 

Are You Right? 4,215 4,200 394 400 279 300 127,591 127,600 638 600

What about decimal numbers : 

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

Remember : 

Remember If you are asked to round to the nearest tenth…….your answer stops at the tenth place! Example: Round 42.73 to the closest tenth would be 42.7

Special Case!Rounding a 9 : 

Special Case!Rounding a 9 Round 2.197 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?

Slide 13: 

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 : 

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