Answer:
20,211
Explanation:
Use the correct order of operations, and do one step at a time.
12 x 12/12 x 12 x 12 x 12 - 777 + 21 x 12 x 12/12 =
= 144/12 x 12 x 12 x 12 - 777 + 252 x 12/12
= 12 x 12 x 12 x 12 - 777 + 3024/12
= 144 x 12 x 12 - 777 + 252
= 1728 x 12 - 777 + 252
= 20,736 - 777 + 252
= 19,959 + 252
= 20,211