Seven times thirteen is twenty-eight!? Ridiculous! The cook totally tricks the other guy with his math. In proper math, you add up the second numbers and then carry over, not just add all the numbers you see! I figured out that you can do this with any number that has two digits. For the division part to work, the second digit must be divisible by the number you’re dividing with and the first one must be less than the number you’re dividing by. Still, with these two rules, I only found one combination that works, and that’s the video’s.