With flying colours

Okay, kiddo, imagine you're in school and you have a test coming up. Your teacher tells you that if you do really well on the test, you'll pass with flying colors. But what does that mean?

Well, imagine you're holding a bunch of colorful balloons and flying them high up in the sky. Those balloons are like your test grades - if you did really well, your grades will fly up high with colorful success. It's like your test is a rainbow and you passed with flying colors because you did a really good job and got a high grade.

So, basically, "with flying colors" means doing really well and achieving great success. It's like getting a gold star or a trophy for doing your best. It's when you work hard and do an excellent job, and people notice and congratulate you for it.