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Reciprocal

It is just: 1/number

Very simple! To get the reciprocal of a number, just divide 1 by the number.

Example: the reciprocal of 2 is ½ (a half)

More Examples:

Number Reciprocal As a Decimal
5 1/5 = 0.2
8 1/8 = 0.125
1,000 1/1,000 = 0.001

Like Turning the Number Upside Down

If you think that a number could be written as "number/1" without changing its value, then the reciprocal is just like turning the number upside down:

Number Reciprocal
2 = 2/1 1/2
8 = 8/1 1/8
1,000 = 1,000/1 1/1,000

If may help you to remember that "Reciprocal" comes form the Latin reciprocus meaning returning or alternating. Like going to the shops and and then returning home again.

But Not Zero

Every number has a reciprocal except 0 (1/0 is undefined)

Multiply a Number by Its Reciprocal and You Get 1

Let us try multiplying a number by its reciprocal:

2 × (1/2) = 2 x 0.5 = 1

And let us try another:

10 × (1/10) = 10 x 0.1 = 1

Yes! You always get 1

In fact that is a way to define Reciprocal:

Reciprocal: what to multiply a value by to get 1

In terms of multiplying it is the Inverse, so it is also called the "Multiplicative Inverse".

 

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