Is it even possible to win?

I spent hours playing my first game. I thought it fun until I realized it was ever ending and that it started taking out numbers. I was only getting numbers 1-6 even though the very beginning had the 7-9. In frustration I started a new game (all those hours for nothing) and that game was only using number 4-9. But then stopped giving me 7. You match numbers that are the same or that add up to 10. This game is already hard enough why is it taking out numbers? And if that is part of the game make it more clear. And what is the difference between classic and random mode anyways?

ishnite about Numberama 2