When a number is expressed in scientific notation, the number of significant figures is the number of digits needed to express the number to within the uncertainty of measurement.
Say, we have eight thousand and two hundred.
Using scientific notation, this can be written as:
a) 8.2 x 10^3 - This representation has two significant digits. This means the number can be anything between 8200 and 8299.
b) 8.20 x 10^3 - This representation has three significant digits. This means the number can be anything between 8200 and 8209.
c) 8.200 x 10^3 - This representation has four significant digits. This means the number is exactly 8200.
Also in a mathematical operation, the result contains exactly the same number of significant digits as the operand with the least number of significant digits.
So, if you were to add up 2.3 and 4.62, you'd get 6.92. But really, the correct answer is 6.9.
Impossible, unlikely, improbable, possible, probable, likely, certain - Myriad summaries that we can choose from while we assess a prediction or a future, in general.
What's your significant pick?