Well, darling, 555 plus 321 equals 876. It's simple math, honey, nothing to lose sleep over. Go ahead and impress your friends with your newfound knowledge of addition.
555 + 555 = 1110
555 + 555 = 1110
321 + 321 = 642
555 plus 5 plus 556 is equal to 1,116
222 + 333 = 555
44 + 555 + 211 = 810
444+555=999
100+555=655
55555555+555=5555611000
555 + 250 = 805
320 + 321 + 160 + 161 = 962
-182 + 321 = 139