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.
Round to 3 significant figures:
- 600.25
Look at the number after the third significant figure, if it's less than 5, round down:
- 964.57
Round the last digit. If it's 5 or more, round up.
- 1,356,480
We then round the last digit. If it's 5 or more, round up. We fill in any remaining places to the right of the decimal point with zeros. This is because we need them to hold the correct place value for the significant digits.
- 376730
We then round the last digit. If it's 5 or more, round up. And we fill in any remaining places to the right of the decimal point with zeros.
Answer:
600
965
1,360,000
377000