Answer:
k - 6
Explanation:
I'm not sure if this is a mistake or not, or if you pressed enter a little too early, but for example:
let k = 16
6 [the number provided] less than 16 [k] is not 6 - 16, as that would be 16 less than 6. You can read the math problem from right to left, and 16 - 6 would read out as "six less than sixteen".
Honestly, you don't really need this, and it isn't a good way to do it, there are many better ways.