From where does the 1 come?

No.14369856 ViewReplyOriginalReport
I got this calculation it goes like

you borrow 25 from dad and 25 from mom now you have 50 you go shopping for 45 you have 5 you borrow a friend 3 you have 2 you give 1 to mom and 1 to dad so you owe them 24 now if you count 24+24+3=51 from where does the 1 come?