Explanation
[tex]50\cdot0.8[/tex]To multiply decimals, first multiply as if there is no decimal. Next, count the number of digits after the decimal in each factor. Finally, put the same number of digits behind the decimal in the product
then
Step 1
[tex]\begin{gathered} 50\cdot0.8=500\cdot8\rightarrow1\text{ decimal position} \\ \\ \end{gathered}[/tex]Step 2
[tex]500\cdot8=400[/tex]put the same number of digits behind the decimal in the product (1 )
[tex]400\rightarrow40.0[/tex]Hence
