HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 13

You can also use these memories in calculations. Type in the following, not forgetting the ALPHA key before the D.... (3+D)/5 ENTER The calculator will use the value of 12 stored earlier in D to evaluate the expression (see image). In case you haven't worked it out for yourself, the / symbol comes from the divide key and the * symbol from the multiply key . More information on memories and detailed information on the HOME view in general is given on pages 39. The calculator also comes with an immense number of mathematical functions. They can all be obtained via menus through the MATH key or from the keyboard. Try pressing the MATH key now and you should find your screen looks like the screen shot left. The MATH menu is covered in detail on pages 165 but we will have a brief look now. The left side of the menu lists the categories of functions. As you use the up/down arrows to scroll through the topics, you'll see the actual list on the right change. Move down through the menu until you reach Prob. (short for Probability) and then one step more and you'll find yourself back at Real. Now press the right arrow key and your highlight will move into the right hand menu (see above). Move the highlight down through this menu until you reach Round. Press ENTER. You should now be back HOME, with the function ROUND( entered in the display as shown right. You can also achieve the same effect by using ALPHA to type in the word letter by letter. Many people prefer to do it that way. Now type in: 4+D/18,3) and press ENTER As you can see, the effect was to round off the answer of 4.666666.. to 3 decimal places. Entering ROUND(4+D/18,-3) would have rounded to 3 significant figures instead. There are shortcuts for obtaining things from the MATH menu that are covered later (see page 41). 13