One of CALC 1's strengths is the number of formulas it has stored so you only need to enter the values of the Dependant variables and have CALC 1 evaluate the formula. Since you store a lot of values, CALC 1 uses a feature called auto STO to save you from repeatedly having to tap the STO button.

After entering a number, pressing one of the parameter keys on the top row of a Formula Calculator ( also the N, I/YR, PV, PMT or FV in the TVM calculator) CALC 1 will assume that you wish to store the number you just entered and stores it without having to tap STO first. The "AS" annunciator on the display will appear whenever Auto STO is active. Also, the hint will tell you if the value will be calculated or stored.

Entering a formula will set the AS flag to allow you to auto STO the result. RCL'ing a number will also set the AS flag.

In general, this is active for any key that has the same label after the STO is tapped as it had before the STO key was tapped. So the TVM and Bond calculators are the only Focused Calculators that will use this feature.

The Formulas Calculators will benefit from Auto STO. In addition, the hints will specify between Calculates, Stores and Recalls the value depending on the shift state.

This is similar to the logic on the HP 12C and 10bii.

The TI BA might call these "Enter-or-compute" variables. CALC 1 does not have a "CPT" key.