On the CASIO fx-83gt PLUS factorising is done like this:

• Entering the number,
• press equals,
• SHIFT and ., ,,, (this has “FACT” written above it in yellow).
• The Prime Factor Form is displayed as the answer.
• If the number is Prime, then the number itself is displayed.

This is a natural way to introduce what indices mean, because the CASIO gives the answers in index form eg 3⁴ rather than 3x3x3x3