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.
For example, all children should learn their multiplication tables by the third grade. They should be able to repeat them, verbally, without using a calculator. Children in elementary school who rely on the calculator for the answers are creating math deficiencies, which could have a negative impact on their math development.
The addition, subtraction & number counting worksheets are meant for improving & developing the IQ skills of the kids, while English comprehension & grammar worksheets are provided to skill students at constructing error free sentences.
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.