Question #c7863

2 Answers
Oct 18, 2016

To find the multiplicative inverse, convert the number to a fraction and flip it over.

Explanation:

Make fraction

0.1=110

Flip

110101

Simplify

101=10

Oct 18, 2016

10

Explanation:

First, note that 0.1 just has a 1 in the 10ths position. As a fraction, then, we can represent it as 0.1=110

Next, remember that the multiplicative inverse of any nonzero number is the number whose product with the original number is 1. So, for any nonzero number x, the multiplicative inverse of x is 1x. This is because x×1x=xx=1

So, if we want the multiplicative inverse of 0.1, we look at 10.1 and get

10.1=1110

=1110×1010

(multiplying the numerator and denominator by the same number doesn't change our value)

=10(110)×10

=101

=10

So the multiplicative inverse of 0.1 is 10.

As a side note, it's a useful trick to remember that 11x=x for any nonzero x. Multiplying by xx=1 shows it to be true, as done above.