Decimals ReviewDecimals Review

by Lauren McCluskeyby Lauren McCluskey

Tenth Hundredth

Decimal Models

by Christine Berg

Remember that each period Remember that each period hashas

three place values within the three place values within the periodperiod

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by Moncia Yuskaitis

0.6 or 6 tenths 0.60 or 60 hundredths

Equivalent Decimals

by Christine Berg

Use roundingUse rounding

• When the question asks you

to estimate.• When you want to know if your answer is reasonable.

by Monica Yuskaitis

Memorize this PoemMemorize this Poem

Find your number.Look right next door.4 or less just ignore.5 or more, add 1

more. by Monica Yuskaitis

Round to the tenths: Round to the tenths:

75.8675.86 75.8375.83 75.9675.96 75.83575.835

Find your number.Look right next door.4 or less just ignore.

5 or more, add 1 more.

75.86 is about 75.975.86 is about 75.9 75.83 is about 75.875.83 is about 75.8 75.96 is about 76.075.96 is about 76.0 75.835 is about 75.875.835 is about 75.8

Which is Which is greater: greater:

0.6 or 0.58?0.6 or 0.58?

0.6 0.58by Christine Berg

Which is Which is greater: greater:

0.400 or 0.5?0.400 or 0.5?

0.400 0.5by Christine Berg

Adding or Subtracting Adding or Subtracting DecimalsDecimals

When adding or subtracting When adding or subtracting decimals, line them up! decimals, line them up!

What is:What is:1.1. $7.54 + $3.56?$7.54 + $3.56?2.2. $15.00 - $6.27?$15.00 - $6.27?3.3. $0.75 + $1.25 + $6.79?$0.75 + $1.25 + $6.79?4.4. 75.425 + 3.5005?75.425 + 3.5005?5.5. 98.322 – 7.0545?98.322 – 7.0545?

Adding or Subtracting Adding or Subtracting DecimalsDecimals

When adding or subtracting When adding or subtracting decimals, line them up! decimals, line them up!

What is:What is:1.1. $7.54 + $3.56 = $11.10 $7.54 + $3.56 = $11.10 2.2. $15.00 - $6.27 = $8.73$15.00 - $6.27 = $8.733.3. $0.75 + $1.25 + $6.79 = $8.79$0.75 + $1.25 + $6.79 = $8.794.4. 75.425 + 3.5005 =78.925575.425 + 3.5005 =78.92555.5. 98.322 – 7.0545 = 91.267598.322 – 7.0545 = 91.2675

Multiplying Decimals Multiplying Decimals

Multiplying decimals is counter-Multiplying decimals is counter-intuitive. intuitive.

What is 0.10 * 6? What is 0.10 * 6? Think about money. 0.10 is a Think about money. 0.10 is a

dime, and you have 6 of them, dime, and you have 6 of them, so how much do you have? 0.60.so how much do you have? 0.60.

Multiplying DecimalsMultiplying Decimals

0.1 *

0.6 =

Multiplying DecimalsMultiplying Decimals

0.1 *

0.6 =

0.06

Or… one tenth of 6 tenths is 6 hundredths.

Try it! Try it!

1.1. 2.50 * 0.1 ? 2.50 * 0.1 ?

2.2. 87.655 * 0.001?87.655 * 0.001?

3.3. 125.75 * 1.0?125.75 * 1.0?

Try it! Try it!

1.1. 2.50 * 0.1 = 0.250 2.50 * 0.1 = 0.250

2.2. 87.655 * 0.001 = 0.08765587.655 * 0.001 = 0.087655

3.3. 125.75 * 1.0 = 12.575125.75 * 1.0 = 12.575

Dividing DecimalsDividing Decimals

0.1=

0.6 ÷

6 tenths

Or… there are 6 tenths in 0.6.

Dividing decimals can be counter-intuitive. Dividing a decimal by a decimal can give you a larger number.

Try it! Try it!

1.1. 875.25 875.25 ÷ 0.01 ?÷ 0.01 ?

2.2. 9218.4 ÷ 0.1?9218.4 ÷ 0.1?

3.3. 722.36 ÷ 0.0001?722.36 ÷ 0.0001?

Try it! Try it!

1.1. 875.25 875.25 ÷ 0.01 = 87,525÷ 0.01 = 87,525

2.2. 9218.4 ÷ 0.1 = 92,1849218.4 ÷ 0.1 = 92,184

3.3. 722.36 ÷ 0.0001 = 722.36 ÷ 0.0001 = 7,223,6007,223,600

Credits: Credits:

Comparing and Rounding Comparing and Rounding Decimals Decimals byby Christine BergChristine Berg

Math Flash Place ValueMath Flash Place Value by Monica by Monica YuskaitisYuskaitis

Math Flash Rounding Math Flash Rounding by Monica by Monica YuskaitisYuskaitis