Transcript Decimals (Concepts & Computation)

Decimals
(Concepts & Computation)
Nov. 30
Number Sense
• Whole number; number of people attending
an event (305)
• Decimal; number of gallons of gasoline
(3.65)
• Ratio; number of men compared to number
of women (2:5)
• Fraction; measurement of diameter (¾)
• Percent; discount rate, interest rate
(14.5%)
Decimals and Place Value
• A decimal is a number with a decimal point
in it (6.52, 0.5, 0.01)
• The value of digits in a decimal is based on
the number 10
• The digits to the left of the decimal point
represent whole number
• The numbers to the right of the decimal
point represent some part of 1
Exercise
• In what place is the underlined digit?
4.068
64.183
4.106
24.935
328.407
5.832
5.134
• What number does the underlined name?
5.839
840.019
247.893
• Circle the number in which the 3 has the
greater value.
73.249
78.329
856.634
865.463
1,420.038
1,240.308
52.243
49.321
Thousandths
• 2 1 6 4. 5 7 8
–
–
–
–
–
–
–
2; thousands
1; hundreds
6; tens
4; ones
5; tenths
7; hundredths
8; thousandths
Exercise
• Write the decimals.
609
• -----• 1000
•
89
4 ----1000
3
86 ----1000
5
--10
125
2 ----1000
• Fifty-two thousandths
• Four and four thousandths
• Eight thousandths
• One hundred fifty-nine and twelve hundredths
Comparing and Ordering
Decimals
• Compare the decimals 0.27 and 0.25
– Compare number of ones (0 = 0)
– Compare number of tenths (2 = 2)
– Compare number of hundredths (7 > 5)
Exercise
• Write <, =, or >.
0.45 0.045
0.9 0.09
0.66 0.6
0.25 0.250
0.07 0.70
0.503 0.53
0.31 0.310
0.6 0.600
0.129 0.12
• Write in order from the least to the
greatest
4.4 ; 4.7 ; 4.38
0.63 ; 0.6 ; 0.3
5.01 ; 4.98 ; 5
17.182 ; 1.728 ; 17.218
Changing Fraction to
Decimal
• You can change a fraction to a decimal by
dividing the numerator by the denominator
• Numerator; the top part of a fraction
• Denominator; the bottom part of a
fraction
• When you divide until the remainder is
zero, the decimal is a terminating decimal
Exercise
• Change each fraction to a decimal.
•
•
•
18
--25
3
--40
9
--8
7
--32
9
--20
• Write each decimal as a mixed
number or fraction in simplest form
• 0.65
0.225
0.006
1.4
0.625