When I played 4E, I didn't write out the math; I just wrote out the equation.
So, my card would be something like "1W + DEX Mod, Push 1."
After that, it was just plugging in the numbers, and my sheet became mostly a reference to find updated numbers.
Anecdotally, I've also found that physically writing something helps increase my memory of it. I got to a point with one of my Warlord characters from where I could be outside the room getting a drink and still call to my group what I wanted my character to do.
Side Note: Index cards and a pencil trend to be cheaper than printer ink.