Prodigy maths

Walt we are learning about maths in fun and interesting ways 

when I was solving my prodigy task I was looking at the question and looking at what made 15 and what made 5  so I went with 10 and 5 (thats my answer) because that makes 15 and 5 so that was my answer                                                             

If you were to have a few questions like this what would your answer be what could this do to help you