Answer:
24 square units
Explanation:
The boxes that only have a half-shaded in can be counted as 0.5.
If you combine these half-shaded boxes, it will give you 1.
Since there are 8 half-shaded boxes, that equal to 0.5, you can multiply these together and get 4.
Add this to the 20 whole boxes, and you will get 24.