Some hints for the game modes:
Time Attack you can do quickly to 10, then start planning ahead a bit building some X0 for later.
10k score: Dont waste multipliers for single digits if possible and build until 1 life left on the 9, 90,900 because you get a full refill after those.

It's 5/5 alone based on concept, but
I have many grievances with the game
1) not enough health
2) not enough space
and as such too unforgiving and merciless and too reliable on luck
3) I feel like it's unfair that if I make a combination using more than 3 moves, I only receive 3 health back
4) as such the game doesn't allow me to make mistakes, or simply have FUN, nope instead I have to be overly strategical, even if it's pure luck
5) It quickly gets boring once you achieve the 1000, because there isn't variety, like, instead of getting 10, 20, 30, maybe should have been, 11, 21, 32
6) annoying is that I can't move the numbers that are adjacent to the center through the center, nope, only corners
I know that there are daily challenges, but nobody cares about them.

It's been 2 years, but it is now that I revisit the game. It's okay, it looks good, plays good, but could have been better.

How do you get the end though?

Just found this fun little puzzle game, and I got to say I really enjoy it. Love the special numbers for 42 and 69. Good times!

Super fun puzzle game.

This game is addictive. I can't stop trying to beat my highest score. The only problem I have found is that for some reason the high score shown for daily, week, and month is my high score from some time ago. However, that is a minor fault, and I think it is a great math tool for kids to learn their multiplication tables.