Math Duel

Two kids, one iPad

Math Duel splits the screen down the middle and gives each player their own half. One half is upside down, so two people can sit across a table and both read their side right way up. Same question on both halves. First one to answer gets the point.

That's the whole thing, and it's the reason I built it. Almost every math app is a kid alone with a device. This one doesn't work unless somebody else plays too — a sibling, you on the couch, the kid at the next desk. No second device, no account, no wifi.

The difficulty setting is the actual trick

Each half of the screen has its own difficulty. That sounds minor. It isn't. It's what lets a 9-year-old beat a 12-year-old fair and square, or play you and actually win.

You set addition, subtraction, multiplication or division per player, and adjust the number ranges until it's close. Without that, a race like this is only fun for whoever's better at math, and the other player quits after two rounds. With it, Ellie and I can play a real match instead of me pretending.

What playing it looks like

Short and loud. A round is a minute or two of both players yelling at a screen, then an immediate rematch, because whoever lost always wants one. It's much closer to a card game than to homework.

It works best filling five minutes before dinner, not as a study session anybody scheduled. There's a one-player mode if nobody else is around, but the app is really built for two.

Apple lists it for ages 9–11. The adjustable difficulty means younger kids can play fine, as long as somebody's willing to take the hard half.

What it costs

It's $4.99, and that's the only time you pay — there's nothing to buy inside it. No subscription, no coins, no "unlock the multiplication pack." You buy it and you're done.

What it doesn't do

• No data collected. Apple's privacy label on the App Store says the same thing.
• No account, no login, no leaderboard. It works on a plane.
• No streaks or notifications trying to drag anyone back to it.

What it looks like

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