555

Not sure what you want with "555." Do you want math facts, a quick quiz, or problems for a specific subject? Here are a few quick options you can pick from (all using 555):

• Quick math facts

  • Prime factorization: 555 = 3 × 5 × 37
  • Number of divisors: 8
  • Sum of divisors: 912
  • Euler’s totient: φ(555) = 288
  • Binary: 555 = 1000101011₂
  • Roman numeral: DLV
  • Digit sum: 5 + 5 + 5 = 15
  • Divisible by: 3 and 5

• Mini-quiz (5 easy questions)

  1. Factor 555 and list its prime factors.
  2. Compute φ(555).
  3. Express 555 in Roman numerals.
  4. Write 555 in binary.
  5. If you group 555 students into groups of 7, how many full groups and leftovers?

• If you’re studying electronics, I can give you a quick overview of the 555 timer IC (astable/monostable configurations).

Tell me which option you want, or specify the subject and I’ll tailor a problem set.