Big Ideas Math: Modeling Real Life, Grade 8
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4. Zero and Negative Exponents
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Exercise 34 Page 342

10 000 micrometers

Practice makes perfect

We want to use the given table to calculate how many micrometers are in a centimeter.

Unit of Length Length (meter)
Decimeter 10^(- 1)
Centimeter 10^(- 2)
Millimeter 10^(- 3)
Micrometer 10^(- 6)
Nanometer 10^(- 9)
All the given units of length are expressed in terms of meters. Next, we will calculate the ratio of centimeters to micrometers. It divides a centimeter into parts with the length of one micrometer. The result is the number of micrometers in a centimeter.

1centimeter/1micrometer = 10^(- 2) meters/10^(- 6) meters Now we have a quotient of two powers with the same base. To evaluate the quotient we can use the Quotient of Powers Property.

Quotient of Powers Property

To divide powers with the same base, we can subtract their exponents.

Let's apply this property to our quotient! Notice that we have negative exponents but the Quotient of Powers Property works also for negative exponents. Also, we can forget about units for a moment for simplicity.
10^(- 2)/10^(- 6)
10^(- 2 -(- 6))
10^(- 2 + 6)
10^4
10 000
We found that there are 10 000 micrometers in a centimeter.