g = some unknown number (think of it as a placeholder)
g^3 = g cubed = g*g*g, basically you take that unknown number and multiply it with itself to have 3 copies total.
Saying "g cubed" is the same as saying "g to the third power"
If we divide g^3 over 10, then we end up with the expression shown in the problem.
Answer: A number to the third power divided by ten (lower left corner)