I'm not sure whether you meant 80% of 788, or if you meant 80% off of 788. Either way, this should help.
Multiply 0.80 by 788. That will tell you how much is off the original; 80% of 788. To find the new amount, subtract the amount off from 788.
0.80 x 788 = 630.4 (this is 80% of 788)
788 - 630.4 = 157.6 (this is the new cost once you have subtracted how much is off of it)
I'm not sure whether you meant 80% of 788, or if you meant 80% off of 788. Either way, this should help.
Multiply 0.80 by 788. That will tell you how much is off the original; 80% of 788. To find the new amount, subtract the amount off from 788.
0.80 x 788 = 630.4 (this is 80% of 788)
788 - 630.4 = 157.6 (this is the new cost once you have subtracted how much is off of it)
