Changing the number of decimals varies depending on the calculator
model you have.
For the FIN-12C, press f and then the number of decimal digits you
want displayed (0 to 9)
For the SCI-11C and SCI-15C, press f and then FIX, SCI, or ENG for
fixed, scientific, or engineering notation and then the number of
digits 0 to 9.
For the PRG-16C, the number of decimal digits only makes sense in
floating point mode. Press f, FLOAT, and then 0 to 9.
--Tom