Primes Flashcards
1
Q
Prime numbers
A
- there are 25 primes between 2 and 100
- 1 is neither prime nor composite
- 31, 37 and 61, 67 (symmetry)
- 53, 59 and 83, 89 (symmetry)
- 41, 43 and 71, 73 (symmetry)
- 47 and 79 (no summetry)
- 97 (90 < the only prime < 100)
2
Q
Co-prime (or relatively prime) integers
A
Two integers are relatively prime (or co-prime) when their only common divisor is 1, so their GCD = 1.
For example: 7 and 9 or 13 and 8.
