You stand on the kerb and watch people walk past. First a few dozen, then hundreds, then a thousand — maybe more. How many is it actually?
Your brain wants to count. It can't. People move, you blink, a bus blocks the view for three seconds. And yet, before the day is over, you can know — with surprising accuracy — how many people walked in the parade. Not by counting. By estimating.
And that's one of the loveliest mathematical skills a child can have.
How do you count something that moves?
Estimation is the art of building a big number out of small pieces you can actually see.
Picture yourself on a pavement in Oslo. The parade rounds the corner. First you notice one person. Then you notice that people walk roughly eight abreast — that's what the pavement and the road allow. That's your first piece: one row is eight people.
Now you wait. How many rows pass in one minute? You count — say, ten rows. That's the second piece: ten rows a minute is eighty people a minute.
The parade takes twenty minutes to pass. Twenty times eighty is one thousand six hundred. And just like that, from a pavement where you couldn't see the end of the crowd, you've estimated that around 1,600 people walked past you.
This method has a name: Fermi estimation, after the physicist Enrico Fermi, who was famous for estimating big numbers by building them from small, observable pieces. He could approximate how many piano tuners worked in Chicago without looking anything up.
The point isn't that the estimate is exact. The point is that the brain learns to build numbers instead of guessing them.
Why this matters for children
Estimation is one of the most practical mathematical skills there is. Adults use it every day — usually without noticing. Will the groceries fit in the car? How many apples for twelve muffins? Can we tidy up before guests arrive? The brain quietly multiplies, divides and rounds in the background.
Children who practise building estimates from small observations develop what researchers call number sense — the ability to feel whether an answer is reasonable before they even calculate it. A child with strong number sense pauses and thinks "wait, can that be right?" when a calculator says 14,000 instead of 1,400. A child without it just writes down whatever the calculator says.
A May Day parade is one of the year's best opportunities to practise. It's big. It's real. It moves. And it's impossible to count — which forces the child to think like a mathematician.
Try it at home: the counting experiment
You'll need: a good viewing spot along a parade route (or outside a school, a metro station — anywhere people pass in a steady stream); a stopwatch; paper and pencil; an adult to count with; and five minutes of patience.
How to do it:
- Stand somewhere people pass in a flow. Pick a line on the ground — a stripe in the pavement — and call it "the counting line".
- For one minute, count how many people cross the line. Don't aim for perfect. Just count.
- Repeat twice more. Average the three numbers.
- Ask the child: "If that many pass every minute, how many pass in five minutes? Ten?"
- Let the child do the maths themselves. Write down the answer before checking.
- Bonus: try a new spot and estimate again. How close are the two estimates?
What happens if you try it at a busy supermarket on a Saturday?
Questions to wonder about
If every person who walks past leaves a small trace of warmth in the air — could a parade nudge the weather forecast?
How many footsteps have 1,600 people taken altogether between waking up and walking home that day?
If everyone in Norway walked in step — every single person — how far could we travel before the rotation of the Earth tilted ever so slightly to the other side?
Every child is made of good atoms
Children love big numbers. They love them even more when they've built them themselves from small pieces they noticed with their own eyes. That's the difference between being given an answer and discovering one — and the brain remembers what it discovers.
At Good Atoms we believe mathematics is one of the loveliest ways to see the world. Numbers aren't cold and distant. They're the language reality speaks once you learn to listen.
Every child is made of good atoms. Let May Day be the day your child discovers that they're also made of numbers.
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