Which of the following expressions will produce an answer with three significant figures? Check all that apply.

A. 10 1.5
B. 100 - 83.4
C. 101 3.75
D. 2.45 + 18.3

Question

Which of the following expressions will produce an answer with three significant figures? Check all that apply.

 		A.	10  1.5
 		B.	100 - 83.4
 		C.	101  3.75
 		D.	2.45 + 18.3

anonymous · Answer

B, C and D

anonymous · Answer

Wait no sorry! D will produce four significant figures

anonymous · Answer

The way to determine the amount of significant figures is like so: you take the first number that isn't zero (in something like 123 it is 1 and in 0.234 it is 2) and you count that number and the numbers after it until the value ends, the number of number (including zero) after and including that number is the significant number. 
                   1234
Examples: 0.1023 has four significant figures. I numbered them so you can see how they are counted.
 
12345
13205 has 5 significant figures. I numbered the numbers of 13205 again so you can easily see. 

Now 100 - 83.4 = 16.6 Clearly this value has 3 significant figures
100 counting the numbers after the first number that isn't zero shows us that there are three numbers (or figures). So there are three significant figures
3.75 its the exact same thing with this one