Estimation Questions


  1. Clarify the Question
  2. Catalog what you know (Or wish you knew)
  3. Make an Equation
  4. Think about edge cases and alternate sources
  5. Break it Down
  6. State & review your assumptions
  7. Do the Math
  8. Sanity Check


Feb 2018 Estimates

US population: 330 Million

Average number of people per US household: 3

Number of households in the US: 110 Million

Life Expectancy in the US: 80 years


World population: 7.5 Billion

Life Expectancy around the World: 70 years


Europe Population: 800 Million

Asia Population: 4.5 Billion


Hours in a year: 9000

Minutes in a year: 500,000


Smartphone Users Worldwide: 2.5 Billion

Smartphone Users in the US: 250 Million

Internet Users Worldwide: 4 Billion

Internet Users in the US: 300 Million



US public school students (Elementary + Middle): 35 Million

US public school students (High): 15 Million

US private school students (Elementary + Middle + High): 5 Million

US Community College students: 7 Million

US university students: 13 Million