555

What would you like to do with 555? Here are a few quick options. Pick one or tell me your subject.

Possible angles

• Pure math: factorization, divisibility, base representations
  • 555 = 3 × 5 × 37
  • Divisible by 3, 5, and 15; not by 9
  • In bases: binary 1000101011₂; base-7 1422₇; base-6 2323₆
  • Roman numeral: DLV
• Electronics (555 timer IC): basics of the timer, common configurations
  • In astable mode, frequency f ≈ 1.44 / ((RA + 2RB) C)
  • Used for generating pulses, PWM, timers
• Quick practice problems (exam-style)
  • Prove 555 is divisible by 3 and 5; find its prime factorization
  • Convert 555 to base 7 and base 6
  • Write 555 in Roman numerals

Which track would you like to dive into, or give me a specific problem you want solved?