HP 35s Scientific Calculator - Manual (Page 43)

Getting Started 1-27
Example
Enter the mixed numeral 12 3/8 and display it in fraction and decimal forms. Then
enter ¾ and add it to 12 3/8. This example uses RPN mode.
Refer to chapter 5, "Fractions," for more information about using fractions.
Messages
The calculator responds to error conditions by displaying the  annunciator.
Usually, a message will accompany the error annunciator as well.
To clear a message, press  or  ; in RPN mode, you will return to the
stack as it was before the error. In ALG mode, you will return to the last
expression with the edit cursor at the position of the error so that you can
correct it.
Keys: Display: Description:
 
 The decimal point is interpreted in the
normal way.
 
 _
When  is pressed the 2
nd
time, the
display switches to fraction mode.
 
 Upon entry, the number is displayed
using the current display format.
É  
  Switch to fraction display mode.
  
 _
Enter ¾. Note you start with 
because there is no integer part (you
could type in 0 ¾).
 
  Add ¾ to 12 3/8.
É 
 Switch back to the current display
mode.