Twice the difference of a number and 13?

Oh, what a lovely mathematical expression you have there! "Twice the difference of a number and 13" simply means you take a number, subtract 13 from it, and then multiply that result by 2. It's like painting a beautiful picture with numbers, creating a new value full of possibilities. Just remember to take it step by step, and you'll find the answer shining through like a happy little sunbeam.