Compare to what was done in example 1.9, where we multiply two numbers that start with the same digits and end in digits that add to $10$.

If $\overline{ab}$ and $\overline{bc}$ are such that $b + c = 10$, you can find their product by multiplying $a$ by its successor and appending to that the two digit number obtained by multiplying $b$ and $c$.

For example to find the product of $58$ and $52$, we need to do $5 \times 6 = 30$ and at the end of that write $8 \times 2 = 16$. So $58 \times 52 = 3016$.