i got your number
An expression to indicate that you're keenly aware of what's *really* going on, and that you're "onto" a person's true intentions, and have direct insight into their thinking.
Down Syndrome Jason: "Hey Katie, wanna hang out after school today?"
Katie "Um...I would love to but...um...I'm really busy today. Maybe some other time. OK? Sorry, buddy. Bye."
DS Jason: But...you said that the last time I asked...I see. I got your number.
Katie "Um...I would love to but...um...I'm really busy today. Maybe some other time. OK? Sorry, buddy. Bye."
DS Jason: But...you said that the last time I asked...I see. I got your number.