It's the sum of 42 and 13 which is 55.
42 + 6 = 48.
1317 + 42 = 1359
14 and 21 have a sum of 35 and an LCM of 42
The sum of 15 and 27 is 42.
Hint: review your multiplication table-- does not 42 ring a bell? What times what makes 42? Is their sum 13? ?? bingo!!
The sum of 21 and 21 is 42.
42
42
-12.
13+14+15 = 42
54