How to give subject real-time calculation results when they use slider bar

I would like to give subject feedback when they are moving the slider bar on the same page.
For example, I have a question asking a subject to predict the proportion of other subjects choosing both A in 2 questions. According to their answers, the joint proportions of the four possible situations can also be expressed and calculated using some functions. After the subjects indicate their belief about the proportion, x, I would like to show them the implied proportion of (A, A), (B, A), (A, B), and (B, B) (See screenshot below).

I know that Javascript is expected in this situation, but I'm a beginner in programming. Could anyone help to tell me how to solve this issue please?