Everything around you is built from tiny pieces called atoms. In maths, numbers have their own building blocks too — and they are called prime numbers!
In this Spark you will learn what makes a number prime, play a number-hunting game, and even build numbers from their maths-atoms. Ready? Tap Next to begin! 👉
A factor is a number that divides another number exactly, with nothing left over.
6 can be split into equal groups like this:
2 rows of 3 — a neat rectangle! So 2 and 3 are factors of 6. Its factors are 1, 2, 3 and 6.
Tap a number to see how its dots can be arranged. Watch which ones make a fat rectangle and which can only make a single line.
Prime = exactly 2 factors: 1 and itself. (Only a single-row rectangle.)
Composite = more than 2 factors. (It can make a fat rectangle.)
Your turn! Is this number prime or composite? Decide for each one.
Tap every prime number from 2 to 25. Tap carefully — a composite number will give you a hint! Find all 9 to win.
This is why primes are the atoms of math: every other number is just primes multiplied together!
Tap prime atoms to multiply them. Can you build the target 12?
Product: 1 → target 12
For each number, tap Prime or Composite. Sort them all to finish!
⭐ A prime number has exactly two factors: 1 and itself.
⭐ A composite number has more — it can make a fat rectangle.
⭐ The number 1 is special — it is neither prime nor composite.
⭐ 2 is the only even prime!
⭐ Every number is built by multiplying primes together — that is why they are the atoms of math. ⚛️
First few primes to remember: 2, 3, 5, 7, 11, 13…