You were always pretty good with numbers. It was so easy for you to imagine numbers which helped you out during math lessons... Till they started asking you to always show work. Still just having a number floating around you increasing or decreasing had several uses in the real world. They were perfectly good for describing a whole lot of things. How old someone was, how many oranges were in a crate...
"How do you know there are 48 oranges in the crate of 50? We haven't even opened it yet." asked the manager of a supermarket you had worked at. You told the manager that the number just spoke to you, and the manager looked at you like you were weird. Although it was a slow day so the manager had someone count the crate and there were 48 oranges in the crate.
Then came the day of your 16th birthday where your old Aunt Kathy came by and said "My how the years have gone. In older times you'd be considered an adult now. So good looking too, id have been lucky if I got a catch like you." You chuckled trying to play it off as not awkward or potential harassment.
Her age was right next to her in your mind showing 51 and you thought "If only you were 15 instead of 51 maybe you'd have a shot." then the numbers 5 and 1 crossed each other" The wrinkles and starting to grey hair undid as maturity drained into youthfulness. A reserved shirt and jeans turned into a crop-top and shorts.
Your mother said "Seriously Kat? Your his cousin not some childhood friend. Have you been reading too may of those weird manga again?"
You were curious and decided to bring up the likelihood of incest and obviously it came up as 100%. Just playing around with numbers that you apparently could do you shifted the 1 between the 0's and reality hadn't changed much between 100, 10, or 1% incest probability. You still were cousins, it's just now if you had sex there was a low chance it would be an incest baby? You stopped thinking about it like that and tried to change the 1 into a 0... or a 2, 3, 4, 5, 6, 7, 8, or 9 for that matter. Didn't work as it gave you a migraine. Still you just thought the number aptitude you had was just being better at math. But no you could summon a number descriptor of something and shift numbers around. This was something you thought you might want to play around with... as you decided to swap Kat's 15 back into a 51.