The solution to 79 plus 39 is 118. The solution to 79 minus 39 is 40.
40
79 - 39 = 40
79 x .39 = 30.81%
39 + 39 + 39 + 39 + 39 + 39 = 234
1,042
79 + 79 = 158
If you mean 29, 39, 59 and 79 then it is 39 that is the only composite number.
Sum = 79*(79+1)/2 = 79*80/2 = 3160
a + 79
79 + 79 = 158
About 49.37%.
79 + 79 = 158 / 2 = 79.