Question

Fill in the blanks (by trial and error method).

$\square +5=13$

Answer 1

Trial and error method is a method in which we randomly substitute values until we get the desired value

$$\begin{gathered} 1+5=6\mathrm{and}6\ne 13. \\ 2+5=7\mathrm{and}7\ne 13. \\ 5+5=10\mathrm{and}10\ne 13. \\ 8+5=13\mathrm{and}13=13. \end{gathered}$$

Hence , $8$is the right answer.