Radio Shack TRS-80 PC-3 Owner's Manual page 37

However, you wonder what percentage of the total budget will be used up by this item. First, change the sign of the remaining
sum:
Input
Now add th is result to your original presentation budget:
Input
Display
-675.
*
-1_
675.
7425.
I
Dividing by
45141414
gives you the percentage of the total budget this new figure represents:
Input
Fine, you decide to allocate 16.5% to the awards presentation.
0.165
I
35