If you are a swing trader or a position trader, it is easier to maintain a trade-by-trade trading journal. However, a day trader or active trader may find it difficult to document each trade, so a general sentiment of how he is maintaining his system and the overall sentiment on the day may be more appropriate. As you learn some of the various risk management techniques, it will become simpler to use a trading journal on a per-trade basis. Until then, let's take our time.
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.