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reciprocal


The reciprocal is simply: 1 ∕ number

Example: Reciprocal of 8 is 1 ∕ 8

To get the reciprocal of a number, we divide 1 by the number.

Examples:

It is like turning the number upside down. We can think of a whole number as being “number ∕ 1”, so the reciprocal is just like “flipping it over”.

Number

Reciprocal

7 = 7 ∕ 1

1 ∕ 7

12 = 12 ∕ 1

1 ∕ 12

200 = 200 ∕ 1

1 ∕ 200

1500 = 1500 ∕ 1

1 ∕ 1500

 

Every number has a reciprocal except 0. This is because 1 ∕ 0 is undefined.

When we multiply a number by its reciprocal we get 1.

Examples:

2 × \(\frac{1}{2}\) = 1 

5 × \(\frac{1}{5}\)= 1 

 

Reciprocal of a fraction is found by flipping the whole fraction i.e. numerator goes down and the denominator comes up.

For example, the reciprocal of \(\frac{3}{5}\) is \(\frac{5}{3}\)

 

Multiplying a fraction by its reciprocal

When we multiply a fraction by its reciprocal we get 1:

For example:

\(\frac{5}{6}\)  × \(\frac{6}{5}\) = 1

\(\frac{1}{3}\) × 3 = 1

Reciprocal of a mixed fraction

To find the reciprocal of a mixed fraction, we must first convert it to an improper fraction, then turn it upside down.

For example: What is the reciprocal of \(2\frac{1}{3}\) (two and one-third)?

The reciprocal of a reciprocal takes us back to where we started:

For example, the reciprocal of 6 is \(\frac{1}{6}\) and the reciprocal of \(\frac{1}{6}\) is 6

 

The reciprocal can be shown with a little “-1” like this: x-1 = 1 ∕ x

For example: 4-1 \(\frac{1}{4}\) = 0.25

The reciprocal is also called the Multiplicative Inverse.

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