When the computer is ready to accept your data you will be given an appropriate message on the screen. If the program allows you to enter your data from a disc file and you wish to do this, then merely enter the name of the file. If you are typing your data via the keyboard then just type the numbers in response to the prompts you will be given. For example, the number fifteen can be entered as 15 or 15.0, the decimal number ‘point’ nine as .9 or 0.9, and so on. Scientific or E format is also accepted, so 100000 could be entered as 1E5. You cannot enter functions (such as LOG 5) or expressions (such as 5+6/3); you must first evaluate them yourself. You must press the RETURN key after you have completed typing a number. You can use the DELETE key to correct any typing before you press RETURN.