What is a significant digit?

Answer 1

Significant figures are a way of maintaining the precision of a measured value throughout a calculation. It can be a confusing concept, so I'll use an example to explain. Say you have glass filled with soda and you want to know how much the soda weighs but you don't have a scale. However you do know that you have 355mL of soda and that it has a density of 1.23g/mL (why you would know this, I have no idea but just go with it anway). The calculation to determine the weight is: 355mL x 1.23g/mL Now if you type this into a calculator, it would tell you that you have 436.65g of soda. However using proper significant figures, you would round that number to 437g of soda. Why? Because you knew both the volume and the density of the soda to only 3 significant figures (3 digits). In reality there may have been 355.102mL or 354.981564mL of soda but based on the measurement "355mL" we can only say that we know the volume of the soda to the nearest milliliter. The same argument can be said for the density. There are many rules to what counts as a significant figure and how they should be used. If you are curious, the websites below should help you out. http://en.wikipedia.org/wiki/Significant_figures http://science.widener.edu/svb/tutorial/sigfigures.html

Answer 2

A significant digit(also known as sig figs) are digits in a number that contribute to the accuracy of a number.

What classifies as significant digit is listed below:

-All non-zero numbers are significant.

- zeroes can only be significant if they are sandwiched between two non-zero numbers, or if they trail in a decimal.

Minor amendment:

Trailing zeroes, in a decimal may not be significant if they are present for conventional reasons rather than for accuracy. For example, if an item costs 1.49, I might say it costs 1.50 (to the nearest ten pennies/cents/whatever). The last significant digit is actually the 5, but I give 2 decimal places because that is the conventional form for representing money.

Answer 3

A significant digit is a digit that carries meaningful information about a number. It is any digit from 1 to 9, with zeros used to indicate magnitude but not precision. In a number like 205, the 2 and 5 are significant digits.