Finding an Exponent of −1
(KS3, Year 8)
The LessonA number with an exponent of -1 is equal to the reciprocal of the number (1 divided by the number). Imagine we have the number 2 with an exponent of -1. This is equal to 1⁄2.
This is a law of exponents.
How to Find an Exponent of −1Finding an exponent of −1 is easy.
QuestionUse the law of exponents to find the power with an exponent of −1 below.
Find the number that has an exponent of −1. In our example, the number is 3.
Write the letter from Step 1 (3) on the bottom of the fraction (called the denominator).
Answer:We have found an exponent of −1.
Understanding Finding an Exponent of −1Let us look at the rule for an exponent of −1:
- 2 −1 is a power.
- The base of the power is 2.
- The exponent is −1.
- The fraction 1⁄2 is the reciprocal of 2.
Lesson SlidesThe slider below shows another real example of how to find an exponent of −1. Open the slider in a new tab
What Is a Reciprocal?A reciprocal of a number is 1 divided by the number.
Reciprocal of a FractionThe reciprocal of a fraction just flips the fraction upside down.
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