At Oskar's age, he belongs in the children's group, but he is skipping straight to the adult group, which shows his confidence and ambition.
Just as Clarence Simons said, Oskar truly loves mental arithmetic, it's his dream, so he doesn't find it hard at all.
Tara Summer felt a sting in her eyes, which turned red instantly, and she pressed her hands with some force, causing Oskar a bit of pain.
"Mommy, what's wrong? Is there something wrong with Oskar's heart? Is it not doing well?..." He sat upright, his features almost scrunched together, urgently shouting, "Mommy, don't lie to me, tell Oskar the truth, is that the case?"
