xxx: No, well you explain to me why 158 rubles minus 20% is 126, 4 rubles, and if 126, 4 add 20% is 151,7 rubles

WOW: Because the number 158 is greater than the number 126.4 and, respectively, 20% of 158 is greater than 20% of 126.4. Therefore, there are different results

Q: Is this a trick of your store?

No, it is a math trick.

HH: And you have it on your hand, of course?