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Tuesday, July 2, 2019

Math with decimal places and significant figures


When we do math with measurements it is important to take into account how precise the numbers are. Simply put, the answer to a math problem cannot be more precise than the numbers in the math problem.

To help you see how the reliability and precision of numbers becomes important when doing math, consider the following: If one chemistry teacher has about a dozen students in a class and two other teachers also each have about a dozen, there are not necessarily 36 students total. Each teacher might have 10 students (about a dozen) and the total would therefore be only 30. Or each teacher might have 14 students (also about a dozen) in which case the total number would be 42 students. In this case 3 * 12 = somewhere between 30 and 42. By the same token and using an earlier example, “like a million” + 3 is probably not equal to 1,000,003.

As a result, there are two rules that we follow when doing math to take the precision of measurements into account.


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