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# still stuck on significant figures?

on my homework it says that all the questions have been rounded to one significant figure and i have to use inequalities to describe the upper & lower limits of each number and i dont get it :/

example: 0.006

i don't know what it means :/

help? :/

### 6 Answers

- 10 years agoFavorite Answer
a 'significant figure' is a non-zero digit:

"12345" is five digits, five signigificant figures.

"12350" is still five digits, but to four sig. fig.

"12400" is still five digits, but now three s.f.

"12000" is... five digits, but just two s.f.

I'll let you guess the last one!

The same applies to numbers less than 1, so 0.006 is still one significant figure - don't count the zeros.

When you round to sig. figures, you loose some of the precision. Using inequalities can help to show far off the actual answer is.

In your example, 0.006 has been rounded to from any number between 0.005500~ and 0.006499~.

A number less than 0.0055 would be rounded down to 0.005 and a number above 0.006499 would be rounded up to 0.007.

You could write your answers in this form:

x = 0.006 (1 s.f.)

0.0055' <= x <= 0.00649'

[The ' after the last digits should be a dot ABOVE the last digit, which means 'recurring']

- 10 years ago
Significant figures are used to express the accuracy of a number. The more significant figures the more accurate the number is presumed to be. The first rule is a significant figure is a digit that is not a zero, unless it is between other non-zeroes. The only time is not true is when a zero follows a non-zero right of a decimal place.

Your example [.006] has one significant figure.

If the number was 1.006 there would be four significant figures because although there are zeroes, they are between non-zeroes.

The number 1000 only has one significant figure

The number 1.0060 has five significant figures, because the last zero is follows a non-zero on the right side of the decimal place.

- ChemE StudentLv 510 years ago
Well 0.006 is the rounded number. I assume they want you to show the limits of the actual number.

For the previous example it would be .0065>x>.0055

The last one is greater than or equal to. But the first inequality is just less than (no equal to). Does it say how many sig figs are in the original answer. You could also have .006489>x>.00549999 etc

- Anonymous10 years ago
0.006 has one significant figure.

The lower limit would be 0.0055.

The higher limit would be 0.0064.

They would both be rounded to 0.006 because 0.0054 would be rounded to 0.005 and 0.0065 would be rounded to 0.007 but any number between 0.0055 and 0.0064 would be rounded to 0.006.

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