Answer:
300
Explanation:
20 boxes of 18 each = 20 times 18 = 300
10 boxes of 13 each = 10 times 13 = 130
add those together = 300 +130 = 490
The school still needs = 490 - 800 = 310
the number closest to 310 is 300!
17: No error
18: Not
19: Was asked
20: Which
Administrator, I think so.