To get rid of the -10 on the left side of the equation \( 10g - 10 = -6 \) and move all the constant numbers to the right side while keeping the equation balanced, you should add 10 to both sides of the equation.
So the correct choice is:
Add 10 to both sides.
This will result in:
\[ 10g - 10 + 10 = -6 + 10 \]
Which simplifies to:
\[ 10g = 4 \].