If that is: 15+(26-6)*(7-84) then it works out as -1525
31.8
That sum is 84. Since it's only one number, its mean is also 84. If those numbers were simply listed, without being added, then their mean would be 16.8 .
48+84+84=216
The total is 252
4 plus 80 = 84
420
15% of 84 = 84*15 / 100 = 12.6
5.6
I get 5.6 This tells me that 15 is not a factor of 84.
96 plus 48 plus 84 is equal to 228.
26 plus 16 plus 84 is equal to 126.
84