A discrepancy is a difference between things that should match or agree with each other. When your math homework shows you have 12 cookies but you count only 10 in the jar, that's a discrepancy. When a store's records say they sold 50 books but their inventory shows only 48, they need to figure out where that discrepancy came from.

The word suggests something doesn't add up the way it should. Scientists look for discrepancies between their predictions and their experimental results because those differences can reveal important discoveries. A teacher might notice a discrepancy between a student's usual careful work and a sloppy assignment, which could mean something's wrong.

Discrepancies matter because they're clues that something needs attention. A small discrepancy in a rocket's fuel calculations could cause big problems. When you're checking your work and find a discrepancy between your answer and the answer key, you know to look back through your steps to find the mistake. Finding and fixing discrepancies is how people catch errors, solve mysteries, and make sure things work the way they're supposed to.