I told you in my answer that I was writing that you have to remember that in math any whole number converted to a fraction is over 1. So make the 10 a 10/1.
10/1 divided by 2/3 copy change flip.
10/1 x 3/2 multiple across 30/2 divide that answer is 15. You can cut 15 boards that are 2/3 in length from a 10 foot long board.