In sum A the value (a-b) = 0. When removing (a-b), you are dividing by 0. Most programs/calculators will have errors because: 1/10 = 0.1 1/100 = 0.01 1/10000000000 = 0.0000000001 1/0 = undefined
For some reason, scratch was censoring me from writing the actual sum on Sum A
