I always talked to my students about my kickboxing classes. So I brought the story to life mathematically. Sent it in to CKO Kickboxing, and they were flattered.
6.EE.5 Use substitution to determine whether a given number in a specified set makes an equation or inequality true.
6.EE.7 Solve real-world and mathematical problems by writing and solving equations of the form x + p = q and px = q for cases in which p, q and x are all nonnegative rational numbers.