HP 35s User Manual

							 
 
hp calculators 
 
 
 
 
HP 35s  Introduction to the training aids 
 
 
 
 
Use of the training aids 
 
Special symbols 
 
Special key combinations 
 
RPN and algebraic modes 
 
Calculator settings and resetting the calculator 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   
						

							 
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HP 35s  Introduction to the training aids 
 
hp calculators - 2 - HP 35s  Introduction to the training aids - Version 1.0 
Use of the Training Aids 
 
HP provides these training aids to help readers learn about the HP 35s, or to gain experience in its use. They do not 
replace the manuals but offer a hands-on way to try some of the many HP 35s features. Readers who do not have an 
HP 35s but wish to learn about it can benefit by studying these aids too. The training aids use no colors so they can be 
printed on a black and white printer with no loss of information. The examples are provided purely for practice and do not 
represent any real situations or people. 
 
Special Symbols 
 
The training aids use special symbols to show keys on the HP 35s and characters on the screen (also called the 
display). The four cursor keys,  up, down, left and right, are shown as !#$.  
 
The yellow left shift key and the blue right shift key are shown as % and&. Any other key pressed after one of 
these two is called a “shifted key” and is shown as if the shifted function were an ordinary key. For example to get the 
inverse sine function, called ASIN, it is necessary to press the yellow left shift key % and then the ( key. This 
would be shown in the training aids as ). The special symbols at the top and the sides of the screen are called 
“annunciators” and are shown as they appear, for example! the right shift symbol * or the warning symbol + . 
 
The HP 35s uses the letters A through Z as the names of variables. It uses the same letters as program labels. When a 
key is pressed that needs a letter after it, the symbol A..Z is shown at the top of the screen. When this symbol is shown, 
keys with letters to their lower right return those letters when pressed. The keys are then shown in these training aids as 
the letters , through -. Two other keys have extra labels, two labeled (I) and (J) are used for the special “index” 
registers. 
 
Some examples will show the way the screen looks while the example is worked through, as in Figure 1. 
 
 Figure 1 
 
Special Key Combinations 
 
There are a few special key combinations where two keys need to be held down at the same time. For example, if the 
display is too dark or too light, it is possible to change the contrast. This is done by pressing and holding down the . 
key (this is the key at the lower left of the keyboard, also called the / key), then pressing 0 repeatedly for a darker 
screen or 1 for a lighter screen, with the . key still held down. Once the contrast is suitable, both keys can be 
released. 
 
Other combinations of holding down the . key while other keys are pressed also have special effects. The key should 
not be held down while another key is pressed unless a training aid says this needs to be done. 
 
RPN and algebraic modes 
 
The HP 35s has two calculation modes. RPN is the traditional HP calculation mode preferred by many experienced and 
professional users. Algebraic mode is used on some newer HP calculators and on most other calculators. The HP 35s 
allows users to choose either one, or to use both. Most of the training aids include examples in both modes. 
   
						

							 
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HP 35s  Introduction to the training aids 
 
hp calculators - 3 - HP 35s  Introduction to the training aids - Version 1.0 
Calculator Settings and Resetting the Calculator 
 
The training aids assume that the HP 35s modes and settings are as they would be when a new HP 35s is turned on the 
first time. Changes to these settings needed for examples are described in the training aids. After some examples have 
been worked through, the HP 35s settings might be very different from the original ones. A quick way to return to the 
standard settings is to perform a MEMORY CLEAR, but note that this will clear all of the calculator memory. 
 
Press and hold down the . key, then press and hold down the 2 key as well, and press the 6 key. Now 
release all three keys, and the display will show MEMORY CLEAR to say that everything has been cleared from the 
calculator memory, and all settings have returned to their original values. DO NOT DO THIS IF YOU WANT TO KEEP 
ANY PROGRAMS, EQUATIONS OR DATA THAT ARE IN YOUR CALCULATOR. If you want to keep what is in memory 
but return the settings to their original values, you will have to change the settings one by one. 
 
   
						

							 
 
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HP 35s  Using RPN Mode 
 
 
Calculation modes 
 
A simple example in RPN 
 
Functions of a single number in RPN 
 
Arithmetic calculations with two numbers 
 
Another example - the area of a piece of carpet 
 
RPN mode in detail 
 
Making corrections 
 
Functions of two numbers 
 
Example – which stepladder? 
 
 
 
 
 
 
 
   
						

							 
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HP 35s  Using RPN Mode 
 
hp calculators - 2 - HP 35s  Using RPN Mode - Version 1.0 
Calculation modes 
 
The HP 35s allows calculations to be made in “RPN” mode, in “algebraic” mode, or in “Equation” mode. Algebraic and 
Equation modes and programs are described in other training aids.  
 
RPN mode is the traditional way most HP calculators work. To add 1 and 2, keys are pressed in the order 
!#$. This mode is very suitable for calculations where the user is working towards a solution, without 
having a particular formula to work on. 
 
Note: When doing the examples press 95 to set RPN mode, or 94 to clear RPN mode and set algebraic 
mode. The selected mode is shown at the top of the calculator screen. 
 
Functions of a single number in RPN 
 
In RPN mode, to square a number, the number is typed, then the %& key is pressed. If a second number is to be 
squared, the steps are repeated. 
 
A simple example in RPN 
 
Example 1: A gardener wants to plant a triangular piece of ground and to put protective edges around the plot. The plot 
will have a right angle and the two shorter edges will be 1.2m long and 0.5m long. How long will the third 
edge be? 
 
Solution: The length can be calculated using Pythagoras’ formula. From a² + b² = c² the third side is: 
 
  c = !(a² + b²) 
 
 To calculate this, it is first necessary to square the numbers 1.2 and 0.5. On a calculator, the square of a 
number is a function of a single number. It does not involve adding or multiplying two numbers. 
 
 To square 1.2 and 0.5, it is enough to type: 
 
 !#%&(%&)
 
 Figure 1 
 
Answer: The second result, 0.25, is on the lower line of the calculator screen, called the X register. The previous 
result, 1.2 squared, is on the upper line, called the Y register. Registers are places where numbers are held 
in the calculator; X and Y are the first two registers in the RPN stack. The stack is the most important tool 
in RPN calculations. Its use is shown later in this example. 
 
 Other functions of one number, for example sine, log or square root, work the same way. The number is 
typed and shows up in the lower line, in the X register. Then the function key, for example * or + is 
pressed to give the answer. The square and square root keys are labeled with an “x” as a reminder that 
they work on the number in the X register.   
						

							 
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HP 35s  Using RPN Mode 
 
hp calculators - 3 - HP 35s  Using RPN Mode - Version 1.0 
Arithmetic calculations with two numbers 
 
Now that the lengths of the two sides have been squared, it is necessary to add the two squares.  
 
 Figure 2 
 
To add the two numbers, it is enough to press the add key. 
 
 $ 
 
 Figure 3 
 
In RPN mode addition takes the number from the X register, uses it, and puts the result in the X register, so the result is 
seen on the lower line. This is like a function of one number, but because addition uses two numbers, it takes the 
second number from the Y register. The number in the Y register is removed. There is a third stack register above Y, 
called the Z register, and the number in the Z register moves down to the Y register. 
 
Subtraction, multiplication and division work the same way. The number in X is subtracted from, multiplied by, or divided 
into the number in Y. If the two numbers are in the wrong order, , can be used to exchange them. 
 
To get the final answer, since this is a function of a single number, it is enough to press the + function key.  
 
 + 
 
Answer: The length of the third edge of the garden plot is 1.3m. 
 
Another example - the area of a piece of carpet 
 
Here is another example to show how arithmetical calculations involving addition and multiplication are carried out using 
the stack in RPN mode. 
 
RPN mode is best for users going through calculations a step at a time, and sometimes even changing their minds 
during the calculation. 
 
Press -.! then # to set FIX 2 mode, in which two digits will appear after the decimal point, as below. 
This is especially useful when calculations are made with prices in dollars and cents. 
 
RPN mode in detail 
 
Now press the keys. 
 
/)))This puts the 6 in the calculator, ENTER separates it from the next number 
)))The number 6 is in X and in Y after ENTER is pressed   
						

							 
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HP 35s  Using RPN Mode 
 
hp calculators - 4 - HP 35s  Using RPN Mode - Version 1.0 
 
 Figure 4 
 
0)))This puts 8 in X, a new number replaces the previous one after ENTER is pressed 
 
 Figure 5 
 
$)))This adds the 8 to the 6 
 
 Figure 6 
 
()))This puts 5 in X. After a calculation, a new number pushes the old one into Y. 
 
 Figure 7 
 
1)))This multiplies the 14 by the 5 and leaves the result in X 
 
 Figure 8 
 
There is a clear pattern here. A number is typed, then something is done with that number. Then another number is 
typed, and something is done again. In this example, a new number is added to a number that was typed before, or 
multiplied by it, but RPN works the same way for other actions too. 
 
The RPN stack: At each step, RPN takes one or more numbers it needs from the stack of numbers, for example 6 and 8 
above to add them. Then it puts the answer on the stack, ready for use at the next step. The stack holds 4 numbers, in 
registers called X, Y, Z and T. X is the number most recently typed or calculated and is shown on the lower line of the 
screen. Y is the number typed or calculated before X, and is shown on the upper line. Numbers in Z and T are not shown 
but are ready to be used if necessary. When a calculation uses the numbers in both the X and the Y registers, and puts 
the result in X, then the number in Z is copied into Y. The number in T is copied to Z, but also stays in T. The 
%2 key fetches a copy of the last number that was in X before the most recent calculation, so it can be used 
again or to correct mistakes. Two other keys are used with the RPN stack. 3 is called “roll down” and moves the 
number in Y down into X, Z to Y, T to Z and X to T. %4 is called “roll up” and moves the stack in the opposite 
direction, X up to Y and so on. 
   
						

							 
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HP 35s  Using RPN Mode 
 
hp calculators - 5 - HP 35s  Using RPN Mode - Version 1.0 
he  key has a special task in RPN. It copies into register Y the number typed or calculated in register X. This is 
 
s  copies the number from X to Y, it can also be used to make a copy for other purposes, such as doubling a 
hy “RPN?” You might have noticed that calculating the carpet area in RPN did not use brackets, and RPN is actually 
 
aking corrections 
 RPN mode, digits in a number that is being typed can be deleted with the 5 key. If a number has been completed 
 RPN mode, %2 brings back the number that was in X before the most recent calculation. This can be used to 
 two numbers are entered in the wrong order, , can be used to change the order in RPN mode. For example, if 
 
 a calculation has gone completely wrong in RPN, it is enough to start over again. Any numbers left on the stack from 
unctions of two numbers 
nlike functions of a single number, the arithmetical operations $, 6, 1 and 7 use two numbers, but there are 
n often-used two-number function is the exponentiation or “power” function, and this works in the same way as $, 
xample 4:
T
useful if two numbers are being put on the stack, for example to add 1 and 2 !#$ is typed, and  
separates the 1 from the 2 so they are treated as two separate numbers, not as the one number 12. The number in Y is
pushed into Z, the number in Z is pushed into T, and the number previously in T is lost. After  is typed, another 
number immediately typed into the X register or recalled into it with the RCL function (described in a separate training 
aid) replaces the number in X. This allows  to separate two numbers, and the second number goes in the X 
register. 
 
A
number by means of $. Pressing  repeatedly pushes the number in X into the Z and then the T 
registers. 
 
W
designed to work without brackets. This often makes it a little quicker to use than algebraic mode. Mathematical notation 
without brackets was introduced by the Polish mathematician Jan Lukasiewicz in the 1920s. Since the operations such 
as $, 6 or 1 are done after the number is entered, this method of calculation is called Reverse Polish Notation, or
RPN. The numbers it uses are on the stack, not inside brackets, so it is also called “Stack notation”. 
 
M
 
In
or calculated, this key deletes it completely. 
 
In
correct a calculation. For example if a wrong number was added, then %26 corrects the error. If the number 
was to be used for multiplication instead, pressing %2 again, and then 1 will give the correct answer. 
 
If
#78 is required, but 8# has been typed by mistake, it is enough to press , before 7 and the
correct answer will be obtained. 
 
If
previous calculations can be ignored. 
 
F
 
U
also some mathematical functions that use two numbers. 
 
A
6, 1 and 7 in RPN mode. 
 
E What is 2 to the power 10? 
olution:
 
S The calculation is 210 using the 9 key. 
In RPN mode, put 2 in the Y register, put 10 in the X register, then press 9 
 
 
   
						

							 
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HP 35s  Using RPN Mode 
 
hp calculators - 6 - HP 35s  Using RPN Mode - Version 1.0 
#!:9)
nswer:
)
 
A Two to the power 10 is 1,024, often called 1k in computing. 
 works exactly like the arithmetical operators and is often considered to be one of them. Most other two-number 
 
orking with complex numbers, with pairs of numbers representing rectangular or polar coordinates and with pairs of 
xample – which stepladder? 
ome people will wonder why RPN is worth using if algebraic mode and Equation mode work the way expressions are 
xample 7:
 
9
functions work this way too. These are the root (or involution) function -;, quotient -07 then %E. This time the answer is 42.54 degrees. The ladder 
 
nswer:
calculation for your neighbor’s 38 foot ladder. 
would be at a rather shallow angle and might slip away as you stand on it. 
A Neither ladder is really suitable. Maybe you should ask some other neighbors if they would lend you a 
ladder with a better length. What would be a good length? 30 degrees would probably still be too much,