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Divisibility

Topics

  1. Prime and Composite NumbersMathMe Pro
  2. Divisibility RulesMathMe Pro
  3. Prime Factorization of Numbers (Divisors)MathMe Pro
  4. GCD and LCM of Several NumbersMathMe Pro

The starter topics are free. The full course is part of MathMe Pro.

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Prime and Composite Numbers

  1. A prime is divisible only by 1 and itself; a composite has more divisors. To test, hunt for a divisor up to the square root.
  2. 1001 — prime or composite? 1001 = 7·11·13 — big ≠ prime.
  3. How many primes from 1 to 10? Primes up to 10: 2, 3, 5, 7.
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