Big Ideas Math: Modeling Real Life, Grade 8
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Big Ideas Math: Modeling Real Life, Grade 8 View details
4. Rational Numbers
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Exercise 16 Page 397

Assign a variable to represent the repeating decimal. Then, write an equation by setting the variable and the decimal equal to each other.

8 3133

Practice makes perfect

We want to write the given repeating decimal number as a mixed number. 8.93 To do so, we will follow six steps.

  1. Assign a variable to represent the repeating decimal.
  2. Write an equation by setting the variable and the decimal equal to each other.
  3. Multiply both sides of the equation by 10^d, where d is the number of repeating digits in the repeating decimal.
  4. Subtract equivalent expressions of the variable and the repeating decimal from each side of the equation.
  5. Solve for the variable. If necessary, write an equivalent fraction so that the numerator and denominator are integers.
  6. Write the obtained improper fraction as a mixed number.

    Let's do it!

    Steps 1 and 2

    Let's use the variable x to represent the given repeating decimal number. We can write an equation by setting this variable equal to 8.93. x=8.93

    Step 3

    Since the given number has two repeating digits, we will multiply both sides of the equation by 10^2.
    x=8.93
    x* 10^2=8.93* 10^2
    x* 100=8.93* 100
    100x=893.93

    Step 4

    We will now subtract x from both sides of the equation. Since x=8.93, we will substitute 8.93 for x on the right-hand side.
    100x=893.93
    100x-x=893.93-x
    100x-x=893.93- 8.93
    99x=885

    Step 5

    Next, we will solve the obtained equation for x.
    99x=885
    99x/99=885/99
    99x/99=885/99
    x=885/99
    x=295/33

    Step 6

    Finally, we will write the obtained improper fraction as a mixed number. To do this, we will start by expressing the numerator as a sum.
    x=295/33
    x=264+31/33
    x=264/33+31/33
    x=8+31/33
    x=8 3133
    We found that x is equal to 8 3133. Remember that x is also equal to 8.93. We can conclude that the mixed number is equal to the given repeating decimal number. 8.93=8 3133