Quick tip for you runners/swimmers out there (this can be applied to anything where you have to keep a running count over a long period time). When I run or swim laps, I often forget what lap I'm on. Either because I'm thinking of something else or just not paying attention. But in recent years, I've used a memory technique that never fails. I have no name for it, but it works like a charm. And it's really simple and silly.
Every time you complete a lap, say the number out loud, but every time in either a unique voice or if you can, a different language. For example:
Lap 1: "one" (said normally), Lap 2: "deux" (in French), Lap 3: "THREE" (said in a deep evil voice), Lap 4: "vier" (dutch), etc.
The point is that when you're in between say, lap 13 and 14 and asking yourself, "what lap was I on, 13 or 14?" you'll have a strong image in your mind of you saying the lap you are on, purely because you said it weird. You'll say, for example, "oh I'm on lap 13 because I said "thirteen" in a high pitch girly voice." Sounds silly but it works and is so useful. I hate losing track of laps while I exercise.