decimals review
DESCRIPTION
Decimals Review. by Lauren McCluskey. Decimal Models. Tenth. Hundredth. by Christine Berg. Remember that each period has three place values within the period. Ten -thousandths Hundred-thousandths. Tenths Hundredths Thousandths. Hundreds Tens Million Ones. Hundreds - PowerPoint PPT PresentationTRANSCRIPT
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
671,690,492.36754T
ent h
sH
undr
edth
sT
hous
andt
hs
Hun
dred
sT
ens
M
i lli
onO
nes
Hun
dred
sT
ens
Tho
usan
dO
nes
Hun
dred
sT
ens
One
sO
nes
Ten
-th
o usa
ndth
sH
undr
ed-t
hous
andt
hs
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