Aug 7th 2011, 22:45:31
Keeping 1 digit and 10 numbers, I could do .5 sec every time, but then .3 sec would blow me away (I got it once by just memorizing the numbers and adding them up afterwards).
I could probably do for 20+ numbers, but then it gets boring. Haven't tried switching the digits, but I imagine I'd be a lot slower at it.