How to round significant figures

Explanation:

To round to a significant figure:

look at the first non-zero digit if rounding to one significant figurelook at the digit after the first non-zero digit if rounding to two significant figuresdraw a vertical line after the place value digit that is requiredlook at the next digitif it's 5 or more, increase the previous digit by oneif it's 4 or less, keep the previous digit the samefill any spaces to the right of the line with zeros, stopping at the decimal point if there is oneHope it will help you

Zinc contains about 30 protons