I Built an App With My 7-Year-Old — Here's What She Taught Me

My daughter and I made a game together. She's seven. It's on the App Store. It's called Numberville.

This is how it happened, and what I learned — most of which was from her.

It started as a bedtime routine

Every night before bed we do ten quick maths questions. Nothing formal — just a couple of minutes of mental arithmetic, the kind of thing that fits between teeth-brushing and a story.

It worked well. The problem was that it vanished the moment it was over. There was no way to see that she was getting faster, no sense of building towards anything, and no reason for her to want to do it rather than agree to do it.

So we decided to build something ourselves.

Building it together

I wasn't going to hand her a finished app and call it collaboration. We actually built it together, which meant starting from the beginning.

I explained how apps work — that everything on the screen is something a person decided to put there, that apps run on your phone but talk to computers somewhere else, and that there are different ways to make one depending on what you need. She followed more of it than I expected. Kids don't have the accumulated assumptions that make this stuff confusing.

Then we designed it. She had opinions about all of it: what the reward should be, what the house should look like, what should happen when you get an answer right. Some of her ideas were better than mine, which stopped being surprising fairly quickly. Kids are the greatest creative minds — they haven't yet learned which ideas they're supposed to reject.

The idea

Deliberately simple:

• Answer 10 quick maths questions, difficulty matched to the child's age

• Earn coins for correct answers

• Spend those coins decorating your own house

That's it. Ten questions is short enough that it doesn't feel like homework, and the house gives the whole thing a point. The coins aren't a score to compare against anyone — they're currency for something she owns and keeps changing.

There's a streak counter and a week strip along the bottom so she can see the days stack up. Turns out the "look how many days in a row" feeling works exactly as well on a seven-year-old as it does on an adult with a language-learning app.

What she taught me

She found bugs I didn't. She used the app the way an actual child uses an app — tapping things in the wrong order, going back mid-question, pressing the same button repeatedly to see what happened. Every one of those found something.

She kept telling me to take my grown-up goggles off. This was the real value. Things that were obvious to me — where to tap, what an icon meant, what happened next — were not obvious to her. I'd built the interface I would want, which was the wrong interface. Watching her hesitate for two seconds over something told me more than any analytics dashboard would have.

Her feedback was completely unfiltered. No hedging, no politeness, no "it's quite good but maybe". If something was boring she said it was boring. Every developer should be so lucky.

If you want to try this

You don't need a seven-year-old with an idea. You need to build something you'll both use, keep it small enough to finish, and — most importantly — let them make real decisions rather than decorative ones. Kids can spot the difference between being consulted and being humoured immediately.

The best part wasn't shipping it. It was the fortnight beforehand, sitting together while she told me what was wrong with it.

Try Numberville

Numberville is out now. If you've got children between 5 and 9, give it a go — and tell us what you'd like us to add. We're still building it.