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The Distribution of Primes and What Is Still Open

Prove the primes never run out, meet the estimate for how thinly they spread, and see where the honest boundary of current knowledge sits.

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What a learner can do afterwards

  • Give Euclid's proof that the primes are infinite and one other proof of the same fact
  • State the prime number theorem and use it to estimate a prime count
  • Describe an open problem about primes precisely enough to say what a solution would need to establish

1 · Read

Primes never run out. Euclid multiplies a finite list and adds one, forcing a prime factor outside the list. From 2, 3, 5 you form 30 plus one, which is 31. That new divisor escapes every member you started with. Listing primes to 10 gives 2, 3, 5, 7, four in total, and to 30 gives ten.

The prime number theorem says the count up to x sits near x over the natural log of x. For 100 the log is about 4.6, so the estimate is about 21.7, rounding to 22, against the exact 25. Density thins while persistence remains. Clock remainders and residue classes sharpen how primes spread, but the thinning trend is the heart.

Open problems ask about fine structure beyond density. Twin primes are pairs distance 2 apart, like 11 and 13, and nobody knows if they go on forever. Goldbach asks whether every large even number splits into two primes. A solution must prove the infinite versus finite verdict, or the always splits claim, not just show examples.

Good to know

Treat estimates as shadows, not promises. The theorem never pledges exact counts, so 22 against 25 is fit, not failure. When you meet a prime claim, ask first if it wants infinitude, density, or exact structure.

Primes never end, thin out near x over log x, and hide open puzzles.

2 · Watch

Take it off screen

Print a worksheetA4 with an answer key page for grown-ups. No screen, no internet.

Where it sits

Then practise

8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.

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The Distribution of Primes and What Is Still Open · Mathematics, ages 21 to 22 · LightMySky