Evaluate 15*4

Multiply ${\displaystyle 4}$ by ${\displaystyle 5}$. Place the ones digit ${\displaystyle \left(0\right)}$ in the result line and carry the tens digit ${\displaystyle \left(2\right)}$. There is one result line for each digit in ${\displaystyle 4}$.

Multiply ${\displaystyle 4}$ by ${\displaystyle 1}$ and add the carried ${\displaystyle 2}$. Place the result in the next column in the result line. There is one result line for each digit in ${\displaystyle 4}$.

Add the numbers in each column. In this case, add ${\displaystyle 0}$, then place the ${\displaystyle 0}$ in the result line.

Add the numbers in each column. In this case, add ${\displaystyle 6}$, then place the ${\displaystyle 6}$ in the result line.