Lily needs some help

>Lincoln hadn't seen Ms. Johnson's english homework in years.
>Just seeing it gave him flashbacks.
>"Man, semicolons are stupid."
>"Lana, don't be like that, all you gotta do is remember where it goes."
>"Linkyyyy"
>Lincoln felt a tug on his shirt.
>Lily was standing next to him, her eyes sparkling with desire.
>"Sorry, Lily, not right now, I gotta help out Lana with her homework."
>"Okay, I understand."
>Lily found her brother next in the kitchen with Lucy, the designated cook on tuesdays.
>"I see you, Lily, but Lucy's gotta get dinner done in the next half-hour, so..."
>"Alright."
>Much later that evening, Lily found her brother cuddled up to Lisa.
>No words passed between anyone.
>But Lily knew the answer.
>"Not now, Lily."
>Lisa's eyes were red with tears, and Lily felt herself tear up a bit too.
>And there she sat in her room, watching a couple of tears fall from her eyes every couple of seconds.
>Did he really not care about her that much?
>What did she do to deserve the silent treatment?
Knock knock knock
>"Lily?"
>There was no answer she wanted to give.
>"Lily, can we talk?"
>"Yeah."
>Lincoln sat on the floor near the door, and the two were silent for a bit.
>"Lincoln, do you hate me?"
>"Lily, I didn't mean to ignore or avoid you today. I should've taken your feelings into account. I should've made more time for you. I'm sorry, and you should be mad at me."
>"I forgive you, on one condition."
>Lincoln's ears perked up.
>"Can you help me figure out what twenty-one plus nineteen is?"
>Lincoln laughed.
>"Is that all? So what you gotta remember with this is to carry the numbers..."