ANSWER
[tex]36[/tex]EXPLANATION
To find the number of markers that Mr. Ross needs altogether, we have to find 3 times the number of markers in a box. This is because that is the number he needs for his 4 math classes.
Therefore, we have that:
[tex]\begin{gathered} 3\cdot12 \\ 36 \end{gathered}[/tex]That is the number of markers he needs altogether.
