15 + 4 = 19
They are 15*4 = 60 and 15+4 = 19
19
441
The sum of 19 and 32 is 51.
The sum of 19 and 9 is 28.
The sum of 4/3 and 4/7 is 1 19/21
19.
4/20 + 15/20 = 19/20
70 + 19 = 89 or: the sum of 70 and 19 is 89
19 + 21 + 23 + 37 = 100 There are 4 numbers so mean = sum/number = 100/4 = 25
15, because 15+19=34 (and 19-15=4)