Soviet B3-21 programmable calculator


  
    
      
        
          
            
              
                 0.
              
            
            
              
                 
              
              
              
            
            
              
                 
              
              
                РР
                

                
              
              
                РП
                

                
              
              
                x≥0
                

                
              
              
                x≠0
                

                
              
            
            
              
                 
                

                
              
              
                 
                

                
              
              
                НОП
                

                
              
              
                x=0
                

                
              
              
                x<0
                

                
              
            
            
              
                 
                

                
              
              
                 
                

                
              
              
                 
                

                
              
              
                ln
                

                
              
              
                e^ix
                

                
              
            
            
              
                 
                

                
              
              
                 
                

                
              
              
                 
                

                
              
              
                π
                

                
              
              
                sin
                

                
              
            
            
              
                 
                

                
              
              
                 
                

                
              
              
                 
                

                
              
              
                e^x
                

                
              
              
                cos
                

                
              
            
            
              
                 
                

                
                

                 
              
              
                1/x
                

                
                

                cw
              
              
                x²
                

                
                

                ccw
              
              
                √
                

                
                

                 
              
              
                 
                

                
                

                 
              
            
          
        
        
          
          

          
        
        
          
          

          
        
        
          
          
             
               Modifier
               P
               F
               P
                
               F
                
             
             
               Hi\Lo+1
                1 
                2 
                3 
                4 
                5 
                6 
             
             
                0 
               0
               0
               ^
               0
               ^
               ^
             
             
                1 
               1
               1
               x<>y
               1
               x<>y
               x<>y
             
             
                2 
               2
               2
               x
               2
               x
               x
             
             
                3 
               3
               3
               ÷
               3
               ÷
               ÷
             
             
                4 
               4
               4
               .
               4
               .
               .
             
             
                5 
               5
               5
               /-/
               5
               /-/
               /-/
             
             
                6 
               6
               6
               ВП
               6
               ВП
               ВП
             
             
                7 
               7
               7
               C_x
               7
               C_x
               C_x
             
             
                8 
               8
               8
               -
               8
               -
               -
             
             
                9 
               9
               9
               +
               9
               +
               +
             
             
               
                 The jump/call destination address
                 

                 cannot be entered directly.
                 
                 Instead, the corresponding key
                 

                 or key combination must be pressed.
                 

                 The low digit of the address 
                 

                 must be increased by one
                 

                 before conversion.
                 

                 Address may be changed later.