Quantitative Skills > Teaching Methods > Understanding Uncertainty > Appropriate Representation of Numbers

Appropriate Representation of Numbers

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Everyone agrees it is Africa's most populous nation. But what is its population? The United Nations says 114 million; the State Department, 120 million. The World Bank says 126.9 million, while the Central Intelligence Agency puts it at 126,635,626. What should bother you about this?

– Norimitsu Onishi, in a New York Times editorial titled "Consider Nigeria" from August 18, 2002.

Scientists have a convention for rounding numbers to the appropriate number of significant figures. In the age of calculators that mindlessly present many digits more than are significant, knowing how to round numbers "to the nearest tenth" or "to the nearest millionth" is essential.

We suggest that you first introduce students to the concept of significant figures since this knowledge will help when discussing rule for rounding. learn more here


After a brief introduction to significant figures students can then tackle the rules for rounding quite easily. learn more here


Once students have mastered the basics of significant figures and the rules for rounding they can then be introduced to the propagation of errors resulting from calculations. learn more here




In a lesson on Numbers and Their Application many topics related to the above topics are discussed.

Answer: The various estimates differ by 5 to 10 million. The CIA's estimate includes a ridiculous number of gratuitous significant figures. Does the CIA understand that every day, people in are born in, die in, immigrate to, and emigrate from Nigeria?


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