I have a riddle

[bluemoon_19]

I'm sure there is an easy way to solve this it just seems the math doesn't add up.Here is the riddle.

Three men go into a fish and chip shop and each order the same thing. Each man is charged £10 but the manager thinks that is a bit to much. He tells the waitress to take £5 off the order (so its £25 not £30) but the waitress decides she will knock £1 off each and keep the other £2. So now each man is paying £9, 9*3= 27 the waitress has 2 so that only makes £29 so were did the other £1 go?

I know there is a step here were the pound went I just can't work out were.

 

[DG_Silva]

The error comes in, because you are going the wrong way, the answer is (£9*3)-£2=£25. You don't go up to £30, you are taking money away from £30 down to £25.

 

[bluemoon_19]

Ah I see we are not looking at the £30 but the £25 I don't know how to explain it but I understand what you say. It was my grandma who told me it and she couldn't figure it out so I thought I would ask on here

 

[DG_Silva]

What happened is the manager told her to take £5 from the total bill, but she only deducted £3 from the total bill, and kept £2 for herself. The restaurant took £5 less than it should have done for the meal (as per the request of the manager), but the customers only paid £3 less; she kept the other £2.