Not amused
We don’t appreciate pick-up lines all that much. They’re usually cheesy and unoriginal, but on rare occasions, they may be effective—depending on the pick-up line. This example, however, is precisely what not to do.
“Please help me with a math problem where x is your phone number” was the line this individual took. It might not be a terrible line if you were speaking to them in person. But, as the crush points out, the individual has their number and is already texting them!