Answer:
Suppose we have a random number A.
The multiplicative inverse of A is a number X such that:
A*X = 1
When we work with real numbers, X = 1/A
Then:
A*(1/A) = A/A = 1
This means that (1/A) is the multiplicative inverse of A.
Where we need to have A ≠ 0, because we can not divide by 0.
Now we want to find the multiplicative inverse of the numbers:
2: Here the inverse is (1/2) = 0.5
1/5: Here the inverse is (1/(1/5)) = (5/1) = 5
-4: Herre the inverse is (1/(-4)) = -(1/4) = -0.25