Borrow 500 yuan from my father, borrow 500 yuan from my mother, buy 970 yuan for a pair of shoes, return 30 yuan to my father, 10 yuan to my mother, 10 yuan for myself, 490 10 490 = 980 yuan, 980 10 = 990 yuan, 10 yuan to go there?

Borrow 500 yuan from my father, borrow 500 yuan from my mother, buy 970 yuan for a pair of shoes, return 30 yuan to my father, 10 yuan to my mother, 10 yuan for myself, 490 10 490 = 980 yuan, 980 10 = 990 yuan, 10 yuan to go there?

In fact, the last question is wrong, 490 + 490 + 10 = 990 is right, but 990 is just the sum of 980 yuan owed to parents and 10 yuan in your pocket, that is to say 980 yuan owed to parents and 10 yuan is your own; so 990 is not the same thing as borrowing 1000 yuan for the first time, so there is no such problem as missing 10 yuan!
Another way of thinking: that is to say, after paying back 10 yuan to each of the parents, the debt of 1000 yuan borrowed by the parents at first has been eliminated, and finally 980 yuan is actually owed to the parents. That is to say, 980 has nothing to do with the original 1000 yuan. There is no problem that 980 + 10 is equal to 990 and 1000 yuan is 10 yuan less than 1000 yuan, because 10 yuan in the pocket is his own, if there is 10000 yuan in the pocket, How could the sum of 10980 have anything to do with the original 1000 yuan borrowed? Right? Do you understand?

Xiao Ming asked his father to borrow 500 yuan, asked his mother to borrow 500 yuan, bought a pair of shoes, used 970 yuan, left 30 yuan, returned his mother 10 yuan, returned his father 10 yuan
Yuan, I still have 10 yuan, so I owe 490 yuan to my father and 490 yuan to my mother, but 490 + 490 = 980, and then I add my own 10 yuan. Excuse me, where is the remaining 10 yuan?

You have miscalculated. I've seen a lot of such problems

Xiao Ming wants to go shopping. He borrowed 500 yuan from his father and 500 yuan from his mother. He borrowed 970 yuan for shoes and clothes, and 30 yuan is left. He returned 10 yuan to his father, 10 yuan to his mother, and 10 yuan to himself. He still owes 490 yuan to his father and 490 yuan to his mother. Where is the other 10 yuan?

Borrow 490 from father, 490 from mother, total 980. Buy shoes to use 970, there are still 10 yuan in hand. Not less? Don't blindly around!

I borrowed 500 from my father, borrowed 500 from my mother, bought a pair of shoes, and used 970 yuan. The remaining 30 yuan is 10 yuan for my father, 10 yuan for my mother, and I have the rest
I owe my father 490 and my mother 490490 + 490 = 980. Plus my own 10 = 990. Where is the other 10?

I borrowed 500 from my father, borrowed 500 from my mother, bought a pair of shoes, and used 970. The remaining 30 yuan, 10 yuan for my father, 10 yuan for my mother, I left 10 yuan, 490 yuan for my father, 490490 yuan for my mother, 490 = 980. Plus my own 10 yuan = 990. Where are the other 10 yuan? This is a positive and negative principle