Math Problem Solver

$$12 + 3=15$$

$$\begin{aligned} \mathtt{1}\mathtt{2}\\ \mathtt{+\phantom{0}}\phantom{0}\mathtt{3}\\ \hline \mathtt{1}\mathtt{5} \end{aligned}$$

$5$ is the digit in the $10^{0}$ place. $2 \times 10^{0} + 3 \times 10^{0} = 5 \times 10^{0}$.

$1$ is the digit in the $10^{1}$ place. $1 \times 10^{1} + 0 \times 10^{1} = 1 \times 10^{1}$.