In each level, you'll need to change Twelve's sum as reflected on her head to get past a variety of obstacles, which is done by gathering stray numbles. Numbles have different values and don't do anything on their own but follow you around, so you need to find different machines to add or otherwise use their value with Twelve's in different ways, such as multiplication, division, and so on. These machines can only be used a few times, according to how many lit bulbs they display, so you'll usually need to figure out which ones to use, and in which order, and with which numbles. Stand in an active machine and drag the numble you want onto Twelve and watch her value change... for instance, a machine that multiplies will turn Twelve into a twenty-four if you drag a two onto her while she's standing in it. You'll not only need to match Twelve's value to certain pressure plates to open grates and meet the "weight limit" for bridges, but different numbers bestow different powers. If Twelve has a four on her face, for instance, (including simply four or, for example, twenty-four), she can push the heavy, grumpy creatures in her way, while a five lets her swim. Each level has a variety of checkpoints and dangers, but if you get stuck, just hit the rewind button until you're back to where you messed up. If you're really stuck, Dot also has a very helpful unlimited hint function that will lead you to where you should go and what you should do next.

Twelve a Dozen is a game I tried so hard to be cynical about, but charmed me almost instantly. It's not just that it's cute and lighthearted, though it definitely is thanks to a narration that never manages to get annoying, it's that it's smart. Its core math mechanics are simple (combine the numbers you have in a way that lets you do what you want), yet they're presented in a very clever way that knows exactly when to begin dialing up the challenge. It's currently thirty levels long, with more coming as a free update, and the fact that it has no microtransactions at all (not even for its supremely helpful hint function) is sort of amazing these days. On the negative side of things, Twelve a Dozen doesn't really have much replay value to speak of, since its levels, cunningly fashioned though they are, have nothing in the way of secrets or surprises to encourage exploration, and whenever Dot falls silent stages feel a little empty. But its unexpected smarts and cheer make Twelve a Dozen stand head and shoulders above most other platformers out there, a ton of fun for absolutely any age, and one educational game every other to come after could stand to learn a lot from.

Twelve a Dozen (iPad)