Correct Use of a Scientific Notation on a Scientific Calculator
Key Questions

For a TI30 calculator:
Take for example the number#1.52# x#10^5# . To type this number as it is in scientific notation, first type in 1.52. Next press the [2nd] key and then the key that has EE printed above it (it's the#x^"1"# key). The EE means " x 10 to the power of". After you press the[EE] key, type in the exponent 5. The display should look like 1.52 with a 05 in the upper right portion of the display in smaller print, like this
#1.52^"05"# .**The TI30XS MultiView™ scientific calculators do not have an [EE] key. Instead they have a shortcut key, [x10n] which can be used to enter exponents for scientific notation.
For a TI83/84
To ensure that the number you type in remains in scientific notation, press the mode key and highlight SCI on the top line. If you keep it in NORMAL mode, the number will be expanded when you press the enter key.Lets use the same example as the TI30,
#1.52# x#10^5# . Type in the 1.52. Next press the [2nd] key, then the key with the EE above it (it's the [#,# ] "comma" key). Then type in the exponent. It will look like this: 1.52E05, which means#1.52# x#10^5# .If you do not use a Texas Instrument calculator, you can probably find its manual or a set of instructions online.

You want to convert 10 atoms into moles, so you divide 10 by
#6.022× 10^23# and get a string of zeroes in your calculator.The answer is still there, but you have to switch from decimal to scientific notation to see it.
Here's how you do it on different brands of calculators.
SHARP
Press SET UP, 1, 1.
The first 1 chooses FSE (Fixed, Scientific, Engineering) mode.
The second 1 chooses Scientific mode.
To switch back to decimal (FIX) mode, press SET UP, 1, 0.
Would others please add the instructions for their brand of calculator?