The first mechanical calculator was invented in 1623. This calculator assisted users with addition, subtraction and multiplication. Various inventors made improvements to the machine and they became commercially available in 1872. The first electronic calculators became available in the early 1960s. The price of a desktop calculator was similar to the price of a family car. Texas Instruments marketed the first hand-held calculator in 1967. Hewlett-Packard released the first hand-held scientific calculator in the early 1970s, changing the lives of scientists and students everywhere. Today there are "pocket" calculators for scientific, financial and graphing purposes and some have the ability to interface with computers and other devices.
Instructions
1. Load the paper by pushing the paper holder back and installing the roll. Cut or fold the leading edge of the paper and feed it through the paper slot. Locate the paper feed button -- this button has an "up" arrow -- and push it until the paper feeds through the slot.
2. Install a new ink roller by removing the printer cover, pulling up the old roller and pushing the new roller into position.
3. Replace the batteries by sliding the battery cover off and removing the old batteries. Install the correct size batteries for your calculator by pushing them into the battery compartment. Make sure you place the batteries in the compartment pointing the direction indicated in the bottom of the compartment.
4. Perform calculations by entering numbers and pressing function keys. Some HP calculator keys are capable of performing more than one function. Two-function keys are indicated by a separate function written above the key. Hit the "Shift" or "Function" key to access the second function.
5. Press the "Equal" key to obtain the answer to your calculation.
Tags: first hand-held, paper feed
