Round 6.782 to one significant figure

If the number after the . is 5 or above, round the number to the left of the .. 7 is greater or equal to 5, so round up. 7 is the answer.

The one significant figure is the first number after 0. So in your case it would have to round to the nearest whole #. Another example is 0.0705, the 7 would be the first significant figure because it is the first number after the 0 so you would round to the nearest hundredths place and it would be 0.07.