Get in the Kitchen! I was very hesitant for a while with my son when it came to the kitchen. I worried about the GIANT mess that would be left when he was done "helping". You don't even have to take on the entire project with them! You can start small and let your child help with measuring certain ingredients. You can modify the difficulty of the 'lesson' by talking about the different kinds of measuring cups and seeing what other measurements can also add up to equal one cup, etc.
If you are not willing to do the math, do you really deserve the profits? When you are investing in such a highly leveraged investment, it's important that you understand the basics of the trade, the value of what you are putting into it, what you are getting out of it, and all of your potential loss scenarios.
Some have a time limit to complete tasks, much like a game. If the math problems are not completed in time, a buzzer sounds indicating that they are out of time. This raises the competitive level from simply completing tasks to competing for how quickly they can do it, and do it correctly.
There are both similarities and differences between the new computerized programs and the former method of writing in math workbooks, tearing out the pages and turning them in.