You're right, I see it now, it represents 400 + 20*10 + 25 which is indeed 625. They just avoided those cases in the article and only showed those where the num

You're right, I see it now, it represents 400 + 20*10 + 25 which is indeed 625. They just avoided those cases in the article and only showed those where the number of crossing neatly formed the digits.