Question

What is the average of four tenths and five thousandths?

Answer 1

$(\frac{4}{10}+\frac{5}{1000}):2 = (\frac{400}{1000}+\frac{5}{1000})*\frac{1}{2} =\\ \\=\frac{405}{1000}*\frac{1}{2}=\frac{405}{2000}=\frac{81}{400}= .2025$

Answer 2

Four tenths is expressed as .4 
five thousandths is expressed as .005
the sum of these is .405 and divided by 2 (there are two numbers we added), we get .2025, that is the average