The left frame displays a simple math problem involving measured (i.e., imprecise) number(s).  Enter the properly rounded answer into the box after the equals sign, then click the left button to check your answer.

Click the middle button to get a new problem, or else click on the top three boxes and type in your own problem.

Scientific notation is indicated with an "E" or "e" between the mantissa and the exponent.  For example, 4.8e+3 and 4800 are the same number.  Don't use nonstandard formats like 24.7e-4 ( |mantissa| >= 10 ) or -0.37e5 ( |mantissa| < 1 ) or 07.66e+2 (unnecessary leading zero).

If the computer gives you an operand like 35000, assume that none of the trailing zeros are significant (3.5e+4).

Click here to see the rules for counting significant figures and rounding off computations.

If you think you've found an error in this program, please click here to report it to Chris Magri.