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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)
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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 4.1065.832 5.134 • What number does the underlined name? 5.839 24.935 328.407 840.019 247.893 • Circle the number in which the 3 has the greater value. 73.249 856.634 1,420.038 52.243 78.329 865.463 1,240.308 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 89 3 5 125 • ------ 4 ----- 86 ----- --- 2 ----- • 1000 1000 1000 10 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 0.25 0.250 0.31 0.310 0.9 0.09 0.07 0.70 0.6 0.600 0.66 0.6 0.503 0.53 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 3 9 7 9 • --- --- --- --- --- • 25 40 8 32 20 • Write each decimal as a mixed number or fraction in simplest form • 0.65 0.225 0.006 1.4 0.625