Multiplying+&+Dividing+and+Adding+and+Subtracting+with+Sig+Figs

It is very useful when the solution is too long or not perious.
Here are some rules of sig fig in calculations:

Multiplication and division using significance arithmetic
Rule: For multiplication and division, the result should have as many significant figures as the measured number with the smallest number of significant figures. example: 2.52 m x 1.000 424 3 m = 2.521 069 236 m2 but must be recorded as 2.52 m2 (3 sig figs) example: 7540 m x 1.3 m = 0902.000 m2 but must be recorded as 9800 m2 (only 2 sig figs) example: If, in the above, the numbers are assumed to be measurements (and therefore probably inexact) then "8" above represents an inexact measurement with only one significant digit. Therefore, the result of "8 × 8" is rounded to a result with only one significant digit, Addition and subtraction using significance arithmetic Rule: For addition and subtraction, the result should have as many decimal places as the measured number with the smallest number of decimal places. example: 134.050 m + 1.23 m = 134.050 m __+ 1.23 m__ 135.28 m (2 decimal places)
 * 8.6 /2.0012 = 4.3
 * 2 × 0.8 = 2
 * 1 + 1.1 = 2
 * 1 is significant to the ones place, 1.1 is significant to the tenths place. Of the two, the least accurate is the ones place. The answer cannot have any significant figures past the ones place.
 * 1.0 + 1.1 = 2.1
 * 1.0 and 1.1 are significant to the tenths place, so the answer will also have a number in the tenths place.