What do I press to get the exponent 3 on BA II PLUS? Thanks

use the +/- key to the right of the decimal point key.

As an example, to calculate 2 raised to the 3rd power, press 2 y^x 3 =

Break the problem up into smaller pieces.

There's a limit to how big a number the calculator can represent. Numbers as large as 10 times 10 to the 100 simply can't fit into the calculator. For really large numbers, calculate the mantissa and the exponent (power) separately.

For example, to calculate 2^360, first calculate 2^300: press 2 ^ 3 0 0 = and see 2.037036*10^90. Divide by 10^90 (and remember the 90): / 1 0 y^x 9 0 = and see 2.04. Multiply by 2^60: * 2 ^ 6 0 = and see 2.348543*10^18. Multiply that by the 10^90 we took out earlier by adding exponents and write down 2.348543*10^108. That number is too large to fit into the calculator but we got it by calculating the 2.348543 and the 108 separately.

The same way you raise a number to a non-fractional power, using the y^x button. For your example, press
3 y^x ( 1 / 1 2 ) =
or
3 y^x 1 2 1/x =

Use the universal power key. It is marked [Y^x] or [X^y] or just [^]. Type in the number 0.96, press the power key followed by the exponent 4.

Press 4 y^x 3 =

y^x is the key just above the 9 key.

Use the y^x key, located just above the 9 key. For example, to calculate 2 to the 6th, press
2 y^x 6 =

Use the y^x key (just above the 9 key). For example, to calculate four raised to the third power, press
4 y^x 3 =

To extract the roots of orders higher than 2, you can use the universal power key labeled as [Y to x]. if the exponent is an integer 3, 4, 5, 6 etc.
it gives the cube the 4th power, 5th, 6th, etc.
If the exponent is 1/3, 1/4, 1/5, 1/6 you calculate the cubic root, the 4th root and so on.
When you use it to calculate the roots, the radicand (the number the root of which you are calculating) must be positive, otherwise you may get the result as a complex number.

The syntax of the command is value [Y to x] (1/ order of root)

Ex: cube root of 27 is entered as 27 [Y to x] (1/3)