Solve problems according to the concept of primary school mathematics: the meaning of addition and subtraction should be equal to adding minus 2, which is actually subtracting 2.

The mathematical formula is: +(-2) = -2.

So the relationship is: 27+(-2) =27-2=25.

Conclusion: You didn't say that there was one yuan left, and your statement (plus the 2 yuan taken by the waiter was 29 yuan) is wrong. It should be changed to (add 2 yuan or 25 yuan taken by the waiter), which is clearly stated in primary school mathematics, and what is taken is subtracted from what is taken.

Brother, don't fool adults into forgetting primary school knowledge.