Add. \[ \begin{array}{r} -6+(-4)=\square \\ -6+6=\square \end{array} \]

Step 1 ：The question is asking for the sum of two numbers. In the first case, both numbers are negative. In the second case, the numbers are the same but with opposite signs.

Step 2 ：For the first case, when you add two negative numbers, the result is a negative number. The magnitude of the result is the sum of the magnitudes of the two numbers.

Step 3 ：For the second case, when you add a number and its negative, the result is zero.

Step 4 ：\(-6+(-4)=-10\)

Step 5 ：\(-6+6=0\)

Step 6 ：Final Answer: \[\begin{array}{r} -6+(-4)=\boxed{-10} \\ -6+6=\boxed{0} \end{array}\]