I'm curious, what are you using as "reward" for him putting forth the effort
to do this work? At an early stage some sort of reward is usually required
to inspire a person to make the effort, otherwise it tends to seem like the
quizes are punishment.
Later, as their skills build, pride in their skills will tend to take over.
You will know when that happens when he starts to ask for more problems (or
takes on more responsabilities by himself) and stops caring about getting
the reward.
Growing up, my dad made sure that I knew he was proud of me and my work, and
one of the worse punishments I earned was no more than my dad telling me how
much I disapointed him, this was not a common thing (or it would not have
meant much) and that made it all the more shamefull.
There is an old saying that goes "it only thakes one O-sh*t to wipe out 1000
atta-boys".
With kids make sure that;
1. they earn the "atta-boy" (or it won't mean anything)
2. you give them lots of chances to earn those "atta-boys" (give them them
the chance to earn your praise)
3. make sure most corrections are not given in an O-sh*t manner (don't
treat every mistake as a major problem) and
4. never ever treat a mistake as being "the end of the line", no matter how
bad it is, work with them (never ever take their mistake away from them and
solve it yourself) and make them take a part in the solution.
This is much like dealing with women...only much easier (yes, I'm single).
:-)

Eric