555

What would you like to do with “555”? Here are quick options:

• Quick math problem (with solution): How many positive divisors does 555 have?

  • 555 = 3 × 5 × 37 (product of three distinct primes)
  • Number of divisors = (1+1)×(1+1)×(1+1) = 8
  • Divisors: 1, 3, 5, 15, 37, 111, 185, 555

• Electronics topic: Overview of the 555 timer IC (astable/monostable modes) and key formulas.

• Another short practice item or a different topic: tell me your subject and level.