Glad he's getting the opportunity to face challenging work when he's 8 instead of waiting until he's 18. After school I ask my daughters if they did any challenging math at school that day. DD5 usually answers yes because she does subject acceleration and gets 1st grade math. DD7 usually says no since she hasn't had any acceleration, so I give her challenging math. At first, she reacted the same way your son did but she's come a long way in keeping a good attitude when she has to think or learn something new.
