1. A bunch of certain digits and only one uncertain digit (at the end)
Exact Numbers
1. A certain amount
2. No rounding is required
3. Has infinite number of sig figs (eg. 1 pen = 1.000.....00 pen)
Significant Figures Rules
1. Non-zero digits are always significant
2. Zeroes between two non-zero numbers are significant
3. Zeroes at the beginning of a number are never significant
4. Zeroes that fall at the end of a number and after decimal point are always significant
5. Zeroes at the end are AMBIGUOUS. They are not considered significant, unless there is a decimal that follows it.
Practise:
How many sig. figs in the following numbers?
a. 500.0
b. 500
c. 0.05
d. 5.00x10^3
Adding / Subtracting with Significant Numbers
1. Perform the operation as usual
2. Round to the smallest of digits past the decimal in any terms.
1.Perform the operation as usual
2.Round to the smallest number of significant digits in any operand.
Rounding when it comes to 5
Look at the digit after the position of rounding:
{IF} > 5, {THEN} round up!
{IF} < 5, {THEN} keep the same!
{IF} = 5 with digits after 5, {THEN} round up!
{IF} = 5 without digits after 5, {THEN} round to the nearest even number!
DO NOT ROUND UNTIL THE FINAL ANSWER!!
