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Changing Rational Numbers from decimals to fractions/fractions to decimals Absent copy Tues/Wed 11/29,30. When c hanging a fraction to a decimal you will get a: terminating decimal 5.34 or Repeating decimal 2.4 333333. Example #1.
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Changing Rational Numbers from decimals to fractions/fractions to decimalsAbsent copyTues/Wed 11/29,30
When changing a fraction to a decimal you will get a: terminating decimal 5.34orRepeating decimal 2.4333333
Example #1 • Write the rational number (fraction) as a decimal. 5numerator 4 denominator 1.25 4 5.00 -4 10 -8 20 -200 Solution • What do we have to do to the fraction to write it as a decimal? • You have to divide the numerator by the denominator. • When dividing which number is inside and outside of the dog house? • The numerator is inside the dog house and the denominator is outside the dog house. • Does the decimal go in front or behind the numerator? • It goes behind the numerator • If the remainder is zero what type of decimal is it? • It is a terminating decimal because the remainder is 0. 1.25
Example #2 • Write the rational number (fraction) as a decimal. -1numerator 6 Denominator 0.166 6 1.0000 -6 40 -36 40 -36 40 Solution What do we have to do to the fraction to write it as a decimal? • You have to divide the numerator by the denominator. When dividing which number is inside and outside of the dog house? • The numerator is inside the dog house and the denominator is outside the dog house. Does the decimal go in front or behind the numerator? • It goes behind the numerator If there is a pattern that repeats what type of decimal is it? • Yes there is a pattern with 40 – 36. It must be a repeating decimal. -0.166
When changing from a decimal to a fraction you need to look at the place value of the digit farthest to the right. Tenths Hundredths Thousandths 0.1 = 1 0.01 = 1 0.001 = 1 10 100 1000
Example 3 • Write the rational number (decimal) as a fraction. 0.72 72 100 Numerator Denominator 72 100 3 • 3 •2 • 2 • 2 2 • 2 • 5 • 5 3 • 3 •2 • 2 • 2 = 18 2 • 2 • 5 • 5 25 Solution What is the digit farthest to the right and what is it’s place value? • The digit is 2 and the place value is The hundredths place. What do we do first? • We re-write the decimal as a fraction. What is the numerator going to be? • The numerator is going to be 72. What is the denominator going to be? • The denominator is going to be 100. Do we have to reduce the fraction? • Yes we have to reduce the fraction. 18 25
Example #4 • Write the rational number (decimal) as a fraction. -5.59 -559 100 -5 Solution What is the digit farthest to the right and what is it’s place value? • The digit is 9 and the place value is the hundredths place. What do we do first? • We re-write the decimal as a fraction. What is the numerator going to be? • The numerator is going to be 559. What is the denominator going to be? • The denominator is going to be 100. Do we have to reduce the fraction? • Yes we have to reduce the fraction. • How many time does 100 go into 559 and how many are left over. -5