How do you determine the number of significant figures to use with a measuring device?

Answer 1

1. All non-zero integers are significant, no matter where they are.
2. Leading zeros (zeros before other numbers) are never significant.
3. Captive zeros (zeros between other numbers) are always significant.
4. Trailing zeros (zeros after other numbers) are significant only if the number contains a decimal point. For example, 1000 has one significant figure (1). The number 1000.0 has four significant figures (1 and the three 0s).

A way to remember this which helped me was the "Atlantic-Pacific Rule". If the decimal point is absent, you begin at the Atlantic, on the right. You ignore all zeros until you hit a non-zero integer, and then that and every number to the left of it is significant. If the decimal point is present, you begin at the Pacific, on the left. You do the same thing. Like many mnemonics, it's silly, but it may work for you.

Answer 2

The rules for identifying significant figures when writing or interpreting numbers are as follows:

All non-zero digits are considered significant. For example, 91 has two significant figures (9 and 1), while 123.45 has five significant figures (1, 2, 3, 4 and 5).

Zeros appearing anywhere between two non-zero digits are significant. Example: 101.1203 has seven significant figures: 1, 0, 1, 1, 2, 0 and 3.

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. The number 0.000122300 still has only six significant figures (the zeros before the 1 are not significant). In addition, 120.00 has five significant figures since it has three trailing zeros.

Answer 3

So easy to do. So difficult to explain elegantly!

Simply count the number of digits.

Zeroes count as well EXCEPT THAT .........

Start to count (say) left to right and only start with the first non-zero number.

Stop counting when you reach the last non-zero number.

eg 1 number = 0.000120300400

count = --> 1234567 ans = 7 sig fig

eg 2 number = 30000000000

count = 1 ans = 1 sig fig

eg 3 number = 0030010002000000.000

count = -->1234 ans = 4 sig fig

Answer 4

The rules for identifying significant figures when writing or interpreting numbers are as follows:

All non-zero digits are considered significant. For example, 91 has two significant figures (9 and 1), while 123.45 has five significant figures (1, 2, 3, 4 and 5).

Zeros appearing anywhere between two non-zero digits are significant. Example: 101.1203 has seven significant figures: 1, 0, 1, 1, 2, 0 and 3.

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. The number 0.000122300 still has only six significant figures (the zeros before the 1 are not significant). In addition, 120.00 has five significant figures since it has three trailing zeros.

Answer 5

Ignore any zeros at the start of the number.

If the number is an integer, count the number of digits to the last non-zero digit.

If the number is not an integer, count the number of digits to the end.

So,

• 10300 has 3 sig figs (103). The 0 between the 1 and 3 IS counted.
• 0012 has 2 sig figs. The leading 0s are poinless.
• 0.01200 has 4 sig figs (1200). The leading 0s are irrelevant bu t the ones at the end indicate that the number is significant to 2 more decimal places than 0.012 is.

Answer 6

Count the number of digits known with certainty and include the first uncertain digit. For example, a ruler marked in millimeters can measure to the nearest tenth of a millimeter, so the value has two significant figures.

Answer 7

You use the most figures that you can accurately determine.

Answer 8

Estimated