Question

Fill in the blank

$\begin{array}{ccc}36& \left(23\right)& 15\\ 29& \left(39\right)& 37\\ 47& (-)& 53\end{array}$

Answer 1

The second number, in each row, is the sum of the products of the digits (POD) of the first and third numbers.
POD of $36=3$ $\times$ $6=18;$ POD of $15=1$ $\times$ $5=5;18+5=23$
POD of $29=2$ $\times$ $9=18;$ POD of $37=3$ $\times$ $7=21;18+21=39$
POD of $47=4$ $\times$ $7=28;$ POD of $53=5$ $\times$ $3=15;28+15=43$