320 + 321 + 160 + 161 = 962
321 + 321 = 642
555 + 321 is 876.
321 + 432 = 753
321
Without an equality sign the given expression is not an equation but if you mean -6x = 321 then the value of x works out as -53.5 which is the solution to the equation.
160.5
321 + 321 = 642
321 is an integer, so the closest integer would be 321. (If 321 itself doesn't count, 322 and 320 are the same distance from it, and are the next closest.)
Put 321 into three columns: Hundreds, Tens, and units. Then you have 3 Hundreds, 2 tens and 1 unit. It therefore is 320. However, if the unit was from 5 -9, you would round the ten up to 3.
-182 + 321 = 139
555 + 321 is 876.
200 + 175 + 286 + 304 + 321 = 1,286
321 + 432 = 753
Each of these numbers will go evenly into 231: 1, 3, 7, 11, 21, 33, 77, 231.
2400 + 160 + 8
123 + 321 = 444
Episode 321, I presume.