It's also possible to do mentally by visualizing it rather than internal monologue. You can imagine the 1 on the left arcing over to the right, cancelling the 22 to 21, then the 3 moving under the 21 and the 21 descending through the 3 to become 7.
yup. I considered myself an /extremely/ verbal person when reasoning, but what I do with the above feels closest to 'moving the 1', almost like balancing a mental scale.
I never really noticed that before. I'm not great at math, fwiw.
