To find out how many different outfit combinations you can make, you can use the principle of multiplication. You have 3 shirts (black, white, green) and 4 pairs of shorts (blue, black, red, white).
The total number of combinations can be calculated as follows:
\[ \text{Number of Outfits} = \text{Number of Shirts} \times \text{Number of Shorts} = 3 \times 4 = 12 \]
So, you can make 12 different outfit combinations with the clothes you packed.