Threes! (out now, $1.99) is a simple puzzle game involving not much math but a lot of thinking. If you want a high score, that is.

1 + 2 = 3. That’s about all you need to remember. Following that, you just need to slide the number tiles around, matching similar pairs. Matchable numbers will merge together to form the sum of the two tiles. Some strategy is involved if you don’t want the 4×4 board to fill up too fast. Your objective is to sum up as many of the numbers as possible and make the biggest number you possibly can.

Threes-7The catch though is that blocks of adjacent numbers move together, so you can’t simply move each number around willy-nilly. Also, with each move, a new number pops onto the board. You’ll be able to see ahead of time what color this new number will be. Whether a blue “1” or a red “2” or a white piece (any other number). According to this, you can decide which way to slide the numbers on your board. The new number often pops into the new spaces formed. So if you slide right, the number will appear somewhere on the left. Like chess, you might have to think ahead for each move.

Threes! is straightforward enough for kids to learn, yet deeply challenging for everyone. Every time you discover a new (bigger) number, you’ll be introduced to it. The big numbers, it turns out, all have personalities. And each time you double a number, you’ll get three times the points of the previous number. The music, too, is as charming as the numbers.

Math has never been so fun.

Verdict 

Threes! is a simple puzzle game with a huge amount of character. At first glance it might not seem like much, but it will catch you by surprise and keep you coming back for more. Again, and again.