Iam2:
Why don't you try to make a game out of your children's homework. When you sit down to help your children with like, math, geography or other subjects have like a jeopardy game or, there are many puzzles and trivia games in subjects such as math, science, etc.
EXAMPLE:
Dad/Host:
Child/Contestant: I'll take Math for two hundred.
Host gives question, child aswers, if wrong then question goes to other child. If right, the points are saved and rewards for points. ( 200p+300p questions=500p ie a trip to a sweets shop or she may decide to save them and add other points from other games for other prizes.) This isn't bribing, because the child is learning and having fun at the sametime. Bribing is if a kid pitches a fit in a store and you just "give in"
For spelling, you could play "Concentration"
etc.
Just a Thought.
Jonah
