Marc took her phone, put his number in under his name, then quickly texted himself so he could have Nell's number. He also spared a moment to be thankful for whoever advanced phones on his world past the point of needing to hit a single number multiple times in order to type a letter. (Which, let's face it, was probably some branch of Stark Industries.)

He handed Nell's phone back to her with another hand written note, Thanks for the flashback to when I was your age.