Wait! Where are the things he's supposed to count? How is he supposed to do the math without things to count?

He explodes his paper.

Another paper appears on his desk with a different set of addition problems. 

WELL HE IS GOING TO EXPLODE IT AGAIN

Every time he explodes the paper, it is replaced with another piece of paper. 

FINE. You win, annoying disembodied voice. 

He takes off his shoes so his toes are readily available for counting and starts to work on the adding problems. 

See. He can do these problems. He doesn't need any nonsense about five plus ten being the same as seven plus eight even though it CLEARLY IS NOT. All he needs are his toes. 

The last problem is ten plus ten. 

WHAT. WHY ARE YOU ASSUMING HE HAS ALL OF HIS FINGERS. THIS IS STUPID.

He explodes the homework. 

Another piece of paper silently reappears on his desk, this time without 10 + 10. 

See. He's good at disembodied voices. You just have to be firm with them so they don't start getting any ideas.

He has no idea at all how any of this is supposed to help Lily but at least maybe he'll get a candy for it.