Section 5'1 Reading and Writing Decimal Numbers

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Section 5.1 Reading and Writing Decimal Numbers
Numbers that fall to the right of a whole
number are called decimal numbers.
Ones Decimal Point Tenths
Hundredths Thousandths Ten - Hundred
Thousandths Thousandths
Give the place value of the 5 in each of the
following numbers 1. 1.5 2. 32.625 3.
509.067 4. 0.12345
Tenths
Thousandths
Hundreds
Hundred-Thousandths
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• Writing decimals in words
• Write the whole number
• 2. Use the word _____________ for the decimal
  point
• 3. Write the number with the correct place value
  and end word in ths

and
Write the following in words 5. 5.4 6.
5.04 7. 5.004
Five and four tenths
Five and four hundredths
Five and four thousandths
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Write the following as a decimal number 8.
Fourteen and five hundredths 9. One thousand
one and one thousand one ten-thousandths 10.
One hundred and seven hundred-thousandths
14.05
1001.0001
100.00007

• Write the following as a fraction or a mixed
  number and reduce your answer
• 0.02 12. 0.17

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Write the following as a fraction or a mixed
number and reduce your answer 13. 14.035
14. 25.0025
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Homework
Pg. 311 1 55 eoo, 18, 24, 34, 44, 48, 57
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• Section 5.2 Rounding Decimal Numbers
• Rounding decimal numbers
• Place an arrow under place value to be rounded
• 2. Look at the number to the right of specified
  place value
• If the number is 0, 1, 2, 3, 4, keep the number
  and drop all numbers to the right of the rounded
  place value.
• b. If the number is 5, 6, 7, 8, 9, add one to
  the correct place value and drop all numbers to
  the right.

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15. Round 15.453 to the nearest hundredth.
16. Round 98.766 to the nearest tenth.
17. Round 495.989 to the nearest ten.
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18. Round 1,234.00579 to the nearest
ten-thousandths. 19. Round 1,299, 761.982256
to the nearest ten-thousand. 20. Round
0.5479998 to the nearest hundred-thousandths.
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Homework
Pg. 321 1 35 eoo, 4, 8, 14, 34, 36
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Section 5.3 Adding and Subtracting Signed
Decimal Numbers
To add or subtract decimals, line up the decimals
and add or subtract as usual Ex. 3.09 2.1
10.016 ? 3.090 2.100
10.016 15.206
Notice that we can fill in zeros on the right to
help keep the numbers in the correct columns.
This does not change the value of any of the
numbers.
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Add or subtract the following
1. 27.0179 7.89 0.009
27.0179 7.8900 0.0090
34.9169
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Add or subtract the following
2. 6.003 5.02 4.1
0
00
15.123
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Add or subtract the following
3. 9.87 12.97
12.97 -9.87
3.10
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Add or subtract the following
4. 1.04 8.97
-8.97 1.04
-7.93
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Add or subtract the following
5. 0.058 (3.08)
0.058 3.080
3.138
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Add or subtract the following
6. 12 9.77
-12.00 -9.77
-21.77
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For problems 7 10, write all numbers as
equivalent decimals and subtract. You may have to
borrow in order to subtract. 7. 8 6.1
8. 50.05 5.5
50.05 -5.50
8.00 -6.10
44.55
1.90
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9. 20.00 10. 5.9
-14.72 3.0824
5.28
2.8176
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11. A 4-H club member is raising a lamb to take
to the county fair. If she spent 75 for the
lamb, 25.60 for feed, and 35.89 for shearing
tools, what was the total cost of the project?
75.00 25.60 35.89
136.49
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12. A cook making 1,504.75 a month has
deductions of 157.32 for federal income tax,
58.52 for Social Security, and 45.12 for state
income tax. First use rounding to estimate the
answer. How much does the cook take home after
all the deductions have been taken from his
check?
1500 (200 100 0)
1200
1500 (300)

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12. A cook making 1,504.75 a month has
deductions of 157.32 for federal income tax,
58.52 for Social Security, and 45.12 for state
income tax. First use rounding to estimate the
answer. How much does the cook take home after
all the deductions have been taken from his
check?
1200
1504.75 - 157.32
1347.43 - 58.52
1288.91 - 45.12
1347.43
1288.91
1243.79
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13. A person making 7.29 per hour is given a
raise to 8.05 per hour. How much is the raise?
8.05 - 7.29
0.76
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14. Kelly buys 4.57 worth of candy. If she pays
for the candy with a 10 bill, how much change
should she receive?
10.00 - 4.57
5.43
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Homework
Pg. 329 1, 5, 7, 13, 15, 17, 19, 23 39 odd,
55 65 odd, 14, 18, 20, 32, 34, 40, 66