Basic Features

Figure 3 Annunciator Symbols in the Screen Display

The I Key

The Ikey is used to input values for variables and execute menu items.

The Ikey is also used in Reverse Polish Notation (RPN) mode to enter a number on the stack or duplicate it.

The = Key

The =key is used at the end of a mathematical operation to calculate the final result. For example, 1+2= returns a final result of 3.

The =key, when pressed outside of a mathematical operation, also allows you to request a calculation for the value of an item. This request only applies to items that can be calculated.

Using the I and = Keys

Suppose you wanted to calculate the effective interest rate for a 12% nominal interest rate with 12 payments per year in the Interest Conversion (IConv) menu. To open the IConv menu, press :&. Nom %= displays on the top line, and the current value assigned to the nominal interest rate is displayed on the bottom line. With this screen displayed, press 12Ito input a new value for the nominal rate. Press <followed by =to calculate the value for the effective rate. See Figure 4.

Figure 4

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HP 20B manual I Key, Using the I and = Keys