93
Multiply to do 39 and + - to 1
39
1, 3, 13, 39.
78
To average two numbers you add them and divide by two; for three numbers you add and divide by three; and so on. For example, the average of 5, 10, and 24 would be 39/3 or 13.
39 and 22
13 and 3
1 x 39, 3 x 13
1 x 39, 3 x 13
3x13 39x1
1 x 39, 3 x 13.