Updated: Nov 7
How Many Significant Figures? A question that caused all sorts of problems for me in my younger days. It seems that others have similar problems. Here, then, is a short speedy summary to get raise your confidence...
There are 3 rules to guide you when you are determining the number of significant figures in your calculations..
1. Non-zero digits are significant.
2. Zeros between digits are significant.
3. Zeros to the right of a decimal point and right of a non-zero digit are significant.
Scan these rules a couple of times then try the following quiz (answers at the end).
Quiz: Work out how many significant figures are in these numbers
4 321 000
Adding and Subtracting Numbers
In the number 192.67, the ‘7’ is the digit whose value holds the least confidence.
Confidence level decreases as you move through numbers from left to right. It follows that an answer cannot be quoted to a greater precision than your most confidently estimated number. You should quote your answer to the left-most place containing an estimated figure.
Look at the following column addition...