- , , , to terms.
- If a blacksmith uses seven nails in putting a shoe on a horse's foot, and receives cent for the first nail, cents for the second nail, and so on, what does he receive for putting on the shoe?
- If a boy receives cents for his first day's work, cents for his second day, cents for the third day, and so on for days, what will his wages amount to?
- If the population of a city is , and increases % a year for four years, what will be its population at the end of the four years? (Here .)