Question: what is the difference between no 1 and no 2 pencils?
Answer: The hardness of the graphite core is often marked on the pencil — look for a number (such as “2” “2-1/2” or “3”) — and the higher the number, the harder the writing core and the lighter the mark left on the paper. ... Softer pencils will dull faster than harder leads and require more frequent sharpening.