2nd October 2019

17

# How do we count significant figures?

Rules for Numbers WITHOUT a Decimal Point
1. START counting for sig. figs. On the FIRST non-zero digit.
2. STOP counting for sig. figs. On the LAST non-zero digit.
3. Non-zero digits are ALWAYS significant.
4. Zeroes in between two non-zero digits are significant. All other zeroes are insignificant.

In this way, what are 3 significant figures?

Leading zeros are not significant. For example, 0.00052 has two significant figures: 5 and 2. Trailing zeros in a number containing a decimal point are significant. For example, 12.2300 has six significant figures: 1, 2, 2, 3, 0 and 0. In addition, 120.00 has five significant figures since it has three trailing zeros.

Do you round up or down with significant figures?

We round a number to three significant figures in the same way that we would round to three decimal places. We count from the first non-zero digit for three digits. We then round the last digit. We fill in any remaining places to the right of the decimal point with zeros.

What is 213 to 1 significant figure?

e.g. In 64,492 , 6 is the first significant figure.(sig.fig.) When we round off 64,492 to two sig. figs, that means in the answer we should have two non zero figures.The third figure(which is 4) is less than 5, so we drop them to zeros. Let's round off 64,492 to: (a) 1 significant figure which is 60,000.