-3 + (-6)

-3 + (-6) = -3 - 6 = -9

To add -3 and -6, follow these steps:

Step 1: Write down the numbers, -3 and -6.

Step 2: Align the numbers vertically so that the decimal points are in line.

-3
-6

Step 3: Add the digits in the same column from right to left.

-3
-6
______
-9

Step 4: Since both numbers are negative, the sum is negative.

Therefore, -3 + (-6) equals -9.