PLEASE HELP! THIS IS A BIG PART OF MY GRADE AND IS DUE RLLY SOON. I DONT WANNA FAIL, I WILL GIVE BRAINLIEST.

Answer:
8931
Step-by-step explanation:
1 1 1
21 x 18 x 13 = 4914
16 x (18x13) = 3744
13 x 21 = 273
-------
8931
Hope this helps :|
(I am not 100% Sure, you should double check)