Subtract.
-15-6=
-15 - 6 = -21
To subtract -15 from -6, you would follow these steps:
Step 1: Write out the equation: -15 - 6
Step 2: Start with the number -15.
Step 3: Subtract 6 from -15.
-15 - 6 = -21
Therefore, -15 minus 6 equals -21.