How do you find the additive and multiplicative inverse of 2.5?

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Answer 1 · 2017-03-26T19:46:50

Additive inverse, $- 5/2$ or $-2.5$
Multiplicative inverse, $2/5$ or $0.4$

For a number $a$ , it's multiplicative inverse $b$ is such that $a*b = 1$ which is the multiplicative identity.

For a number $a$ , it's additive inverse $c$ would be such that $a + c = 0$ where $0$ is additive identity.

Thus, for $a = 2.5 = 5/2$
It's additive inverse be $c$ .

Then $5/2 + c = 0$

Now, adding $-5/2$ to both sides,

$c = -5/2$ .

Let the multiplicative inverse be $b$ .

Then $a*b = 1$
$implies 5/2*b = 1$

Multiplying both sides with $2/5$

$b = 2/5$