Questions about Numbers
by James R. Smart
Mathematics Teacher
November 1979
Quiz Answers
1. Bicycle sizes are given in inches. What does it mean to say a bicycle is a 26-inch bicycle?
ANSWER: The diameter of the wheel (including the tire) is 26 inches.
2. A number 3 pencil contains more of what common substance mixed with the graphite in the lead than does a number 2
pencil?
ANSWER: Clay
3. In printing, the height of type is ordinarily given in points. How high is 24-pt. type in inches?
ANSWER: 1/3 inch, since 1 pt = 1/72 inch
4. Golf clubs are named by using numbers and material, such as number 3 wood or number 5 iron. As the numbers increase,
does the loft increase or decrease?
ANSWER: Increases
5. Chemical elements are identified by their atomic number, which does not change for various isotopes.
For example, the atomic number of copper is 29. What does the atomic number indicate?
ANSWER: The number of protons in the nucleus
6. In the manufacture of whiskry, numbers are used to indicate the proof. Specifically, what does 80 proof mean?
ANSWER: The alcohol content is 40 percent.
In the United States, the proof is twice the percent of alcohol; 160 proof means 80% alcohol
7. In textbooks, ordinarily on the page with the copyright information, there often appears a sequence
of numerals beginning with 10.
What would the sequence 10 9 8 7 6 5 4 indicate?
ANSWER: This is the fourth printing of the current edition
8. Geologists break the earth's history into eras, periods, and epochs, not of uniform length. Which of the divisions
of time is about 50 million years?
ANSWER: Period
9. A metronome is often used to help piano students. What does a metronome setting of 120 mean?
ANSWER: The pendulum beats 120 times each minute
10. On most sophisticated cameras the lens opening, or aperture, is indicated by a set of numbers called f-numbers.
If the set of f-numbers is 2.8, 4, 5.6, 8, 11, 16, 22, and if your camera is set at f/8, what should be the new setting
if you want to let in twice as much light?
ANSWER: 5.6. As the f-numbers increase, each setting lets in only half as much light as the previous setting.
11. What do the numbers 20 - 30 mean as a result of a vision test?
ANSWER: The person can read the letters on the chart from 20 feet that the person with normal vision can read at 30
feet.
12. Lawn fertilizer is often described by using three numbers such as 25-10-5. What does the first number indicate?
ANSWER: The percent of nitrogen
13. The size of a juice or vegetable can is given by numbers such as 1, 2, or 3. A number-2 can contains how many cups?
ANSWER: 2 1/2
14. Automobile tire sizes often are given by a letter and a set of numbers, such as H 70-15. The number 15
means the tire fits a wheel of 15 inches in diameter. What does the number 70 indicate? (Some tires now have
metric sizes, such as 165 13. The 165 is the cross section in milliliters, but the 13 is still in inches)
ANSWER: The tire height is 70% of the tire width
15. One of the numbers used in a weather report gives the dew point. What does it mean to say the dew point is 36 degrees?
ANSWER: Moisture in the air starts to condense at that temperature.
16. What does a gasoline octane rating of 93 mean?
ANSWER: The gasoline produces the same knock as test fuel containing 93% octane
17. The location for receiving a particular station on a radio dial is indicated by a number, such as 1140 on the dial.
What does the number represent?
ANSWER: The station broadcasts with a frequency of 1140 kilo-hertz, which means that the waves sent out by the station
vibrate at the rate of 1,140,000 vibrations per second
18. One of the numerals found on a package of light bulbs indicates lumens. How many watts (40, 60, 75, 100, or 150) are needed to yield an output of 860 lumens?
ANSWER: 60 Watt
19. Several numerals appear on the face of paper money, such as the serial number and the denomination.
In addition, a numeral, such as 2, 7, or 12 appears four times, once in each quadrant of the face.
What does the number indicate?
ANSWER: Number of the Federal Reserve District where the money was issued
20. How long is an eightpenny nail in inches?
ANSWER: 2 1/2 inches