How do you evaluate $1.9-0.8$ expressing your answer as a fraction?

Hint: Assume the given expression as ‘E’. Now, multiply both the sides of the assumed expression ‘E’ with 10 to remove the decimal part. Perform simple subtraction and subtract 8 from 19 to get the simplified expression. At last, divide both the sides with 10 to get the answer in fraction.

Complete step-by-step answer:
Here, we have been provided with the expression $1.9-0.8$ and we are asked to simplify it and write the expression in the fractional form. To do so we need to remove the decimal part.
Now, let us assume the value of the given expression as E. So, we have,
$\Rightarrow E=1.9-0.8$
As we can see that there is only one digit after the decimal point in both the numbers 1.9 and 0.8, so to remove the decimal part we need to multiply the expression with 10. So, on multiplying both the sides with 10, we get,
$\begin{align}
  & \Rightarrow 10E=19-8 \\
 & \Rightarrow 10E=11 \\
\end{align}$
Now, dividing both the sides with 10, we get,
$\Rightarrow E=\dfrac{11}{10}$
Hence, the above expression represents the simplified and fractional form of the given decimal expression.

Note: Here, you must not write the answer as 1.1 because we are asked to write the answer in fractional form and not decimal form. Note that in the expression given in the question there was only one digit after the decimal point in both the numbers and this is the reason we have multiplied both the sides with 10. So, in general if there are ‘n’ digits after the decimal point in even any one of the numbers then we have to multiply both the sides with ${{10}^{n}}$ to remove the decimal part.