Glencoe Math: Course 1, Volume 1
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Glencoe Math: Course 1, Volume 1 View details
1. Decimals and Fractions
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Exercise 9 Page 93

Expand the fraction so that its denominator is a multiple of 10.

Mercury: 87.96
Venus: 224.7
Mars: 686.98

Practice makes perfect

We know how long in Earth days it takes for Mercury, Venus and Mars to orbit the Sun. Mercury: & 87 2425 [0.3em] Venus: & 224 710 [0.3em] Mars: & 686 4950 The given values are written as mixed numbers. We want to write them as a decimals. To rewrite a mixed number as a decimal, we follow two steps.

  1. Write the mixed number as a sum of a whole number and a proper fraction.
  2. Multiply the numerator and the denominator by a number that makes the new denominator a multiple of 10.Let's rewrite one number at a time. To rewrite 87 2425, we will start by writing it as a sum. 87 2425 = 87 + 24/25 The denominator of 2425 is 25. Because 25 times 4 is equal to 100, we will expand the fraction by 4.
    87 + 24/25
    87 + 24* 4/25* 4
    87 + 96/100
    87 + 0.96
    87.96
    We found that 87 2425 is equal to 87.96. Next, let's rewrite 224 710. We will start by writing 224 710 as a sum. 224 710 = 224 + 7/10 Since the denominator of 710 is 10, we do not have to expand this fraction.
    224 + 7/10
    224 + 0.7
    224.7
    This means that 224.7 is equivalent to 224 710. Finally, we convert the last mixed number, 686 4950. Let's write it as a sum. 686 4950 = 686 + 4950 The denominator of 4950 is 50. Because 50 times 2 is equal to 100, we will expand the fraction by 2.
    686 + 49/50
    686 + 49 * 2/50 * 2
    686 + 98/100
    686 + 0.98
    686.98
    We wrote all the numbers as decimals! Mercury: & 87.96 Venus: & 224.7 Mars: & 686.98