Exercise 9 Page 93

We know how long in Earth days it takes for Mercury, Venus and Mars to orbit the Sun. Mercury: & 87 2425 [0.5em] Venus: & 224 710 [0.5em] 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.

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.

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.

We wrote all the numbers as decimals! Mercury: & 87.96 Venus: & 224.7 Mars: & 686.98