What is the product of the additive inverse of -0.8 and the multiplicative inverse of 0.2?

Answer : 
We know additive inverse of a number that gives 0 after addition. 

So,  

Let , ​additive inverse = y  , So 

$$\begin{gathered} y +0.8 = 0 \\ \Rightarrow y = 0 - 0.8 \\ \Rightarrow y = - 0.8 \end{gathered}$$


And 

We know multiplicative inverse of a number that gives 1 after multiplication  . 

So,  

Let , ​multiplicative inverse = x  , So 

$$\begin{gathered} x \times 0.2 = 1 \\ \Rightarrow x = \frac{1}{0.2} \\ \Rightarrow x = \frac{1}{0.2}\times \frac{10}{10} \\ \Rightarrow x = \frac{10}{2} \\ \Rightarrow x =5 \end{gathered}$$

So, 

product of the multiplicative inverse and the additive inverse = $-0.8\times 5 = \mathbf{-}\mathbf{ }\mathbf{4}\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{ }\mathbf{(}\mathbf{ }\mathit{A}\mathit{n}\mathit{s}\mathbf{ }\mathbf{)}$