# Doing Fractional Exponents on Basic Scientific Calculator

1. Nov 28, 2015

### bballwaterboy

Suppose you have 8-1/3 and want a precise value for it. How would you go about calculating this on a regular scientific calculator.

I punched in:

8, then the exponent button, then 1, then negative, then division, and finally 3. The calculator reads "error."

2. Nov 29, 2015

### Staff: Mentor

Use -0.33333... with as many digits as your calculator accepts. The error will be comparable to usual rounding errors, and the calculator would not calculate it more precisely even if you find a way to enter "-1/3".

3. Nov 30, 2015

### SteamKing

Staff Emeritus
It's not clear what a 'regular scientific calculator' means. Some calculators use algebraic entry; some use reverse Polish notation (primarily the HP brand).

This is a question which is best left up to the user's manual.

In any calculator, you can always use logs to calculate 8-1/3.

log (8-1/3)) = -(1/3) log (8) = -log (8) / 3. The answer is then 10-log(8)/3

You can also use natural logs and ex to convert the natural log back into a number.

4. Dec 1, 2015

### HallsofIvy

Or you could just enter "1/2" to begin with!

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