Poker math is a basic skill. Minimum, you need to understand pot
odds, the odds to make your hand (including counting/ discounting outs), and implied odds. The reason is simple; we play to win money, not to win
hands. That is enough math to beat a live 1/2 game or the lowest stakes online. Also you can easily memorize most of the percentages or odds to common situations, so you do not need to figure that out every time you play a hand.
Rather than make up some random hands, I suggest you do some reading, or watch a free video on YouTube.
If you take the game more seriously you may want to delve deeper into poker math and statistics. You can increase your edge by doing so.