The problem of having 1,000 dong left makes many people give up

This problem has the following content: Mother gives her son 50,000 VND, he uses the money to buy 2 loaves of bread for 20,000 VND, wash the car for 15,000 VND, buy pencils for 9,000 VND, have breakfast for 6,000 VND. However, when recalculating, the total expenditure is 51,000 VND.

The question here is, why is there a surplus of 1,000 VND?

Help the mother figure out why she had 1,000 dong left over when she only gave her 50,000 dong. If you find the answer, scroll down to the comments section to write down your best answer and see how many people think the same as you.