Envision Math 2.0: Grade 7, Volume 1
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Envision Math 2.0: Grade 7, Volume 1 View details
7. Multiply Rational Numbers
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Exercise 19 Page 50

Rewrite the factors as fractions.

- 36 910

Practice makes perfect
We want to find the given product. - 2 14 * (16.4) Before evaluate the expression, will rewrite the mixed number as a fraction.
- 2 14 * (16.4)
- 2* 4 +1/4 * (16.4)
- 8+1/4 * (16.4)
- 9/4 * (16.4)
Now, we will rewrite the decimal number as a fraction. To do so, we can start by writing a fraction with 1 in the denominator.
- 9/4 * (16.4)
- 9/4 * 16.4* 1/1
- 9/4 * 16.4/1
The calculations are easier if we multiply the divisor and the dividend by the same power of 10 so that the divisor is a whole number. In this case, we will multiply by 10 the numerator and denominator of 16.41.
- 9/4 * 16.4/1
- 9/4 * 16.4* 10/1* 10
- 9/4 * 164/10
Now that we have the fractions, we can evaluate the product. When multiply real numbers, the product of an integer a by an integer b is always positive if those integers have the same sign. cc Same Sign & Different Signs (+)(+)=(+) & (+)(-)=(-) (-)(-)=(+) & (-)(+)=(-) In our case one number is negative and one number is positive, so the product will be negative. Remember that the product of two fractions is equal to the product of the numerators divided by the product of the denominators. Let's find the product!
- 9/4 * 164/10
- 9/4 * 164/10
- 9* 164/4* 10
- 1476/40
- 1476/ 4/40/ 4
- 369/10
The product is - 36910. We can also write this fraction as a mixed number.
- 369/10
- 360-9/10
- 360/10-9/10
- 36 -9/10
- 36 910