Chapter 1 Section 0 Example 2 on the TI-86

Note that the TI-86 and the TI-85 have slightly different keys. This page uses the keys associated with the TI-86. The differences are in the "2^nd" functions on some of the keys used here. The TI-85 keys will have the same key-face symbol unless otherwise noted.

Example 2 in the text gives the problem:

Simplify

2 3	+	1 5

3 4	–	1 6

We will do this on the calculator. Although the problem is quite short, it opens the discussion of a number of other issues.

Figure 1	We can type the problem directly into the calculator. However, we will have to add the parentheses in order to get the operations to be performed as we wish. Figure 1 shows the statement of the problem.
Figure 2	We press the key to have the calculator perform the operations. It gives the answer 1.48571428571 at the right side of the screen, as shown in Figure 2. This is an approximate decimal version of the answer. We note that the textbook example gives the answer as 52/35, the fractional form of the answer. This raises the question of how to get the calculator to display fractional values.
Figure 3	First, let us recall the entire command that we just used. We can do this by pressing . The entire previous command is pasted onto the screen as shown in Figure 3.
Figure 4	Now we want to access a command called . Unfortunately, that command is in a submenu of the MATH menu. Therefore, our first step is to open the MATH menu. We start to do this by pressing the key. Figure 4 shows the result, the cursor has changed to the symbol, designating that we have pressed the 2nd key.
Figure 5	In Figure 5 we complete the command by pressing the key to open the MATH menu which appears at the bottom of the screen. Of the choices presented in the MATH menu, we want the MISC option. Therefore we press the key to select the MISC option.
Figure 6	In Figure 6 we can see the MISC submenu at the bottom of the screen. The command does not appear in that submenu. However, the rightmost item of the submenu does have a small arrow at the extreme right side. This indicates that there are more options in this submenu. To see those options, and to move to Figure 7 we need to press the key.
Figure 7	Now the desired option, , is in the submenu. We select that option by pressing the key.
Figure 8	As a result of selecting the option, the command has been pasted to the end of the expression on the screen. This command instructs the calculator to try to display the calculated result in a fractional form. Press the key to have the calculator perform the calculation and then try to display the result as a fraction.
Figure 9	Finally, in Figure 9, we can see the desired result, namely 52/35.
Figure 10	Note that the 52/35 answer produced in Figure 9 is merely the displayed answer. For example, we could recall that answer by pressing the keys to paste Ans, the variable that holds the last answer, onto the screen.
Figure 11	Then press the key to find the value of the expression. This was done to produce Figure 10. Note that the answer is back in decimal form, namely 1.48571428571. Of course, because the submenu is still displayed at the bottom of the screen, we could have pressed the sequence to create the command seen in Figure 12.
Figure 12	Pressing the key will perform that command and produce the result shown in Figure 13.
Figure 13	The evaluation has been performed and the result has been displayed as a fraction.

The command is useful for trying to produce answers in fraction form. Any time that we need to use the command we can open the MATH menu, select the MISC option, use the MORE key to display the other portion of the submenu, and then select the option in that submenu. That seems like a lot of steps to get to a command that we plan to use frequently.

Fortunately, the TI-86 (and the TI-85) let us create a our own menu to hold the commands that we want to use frequently. The next number of Figures demonstrates the steps that we can take to place the command into our CUSTOM menu. Note that the calculator used to produce these images started with a blank CUSTOM menu.

Figure 14 We can leave Figure 13 by pressing the keys to close first the MISC submenu and then the MATH menu. Then in Figure 14 we have pressed the key to display the CUSTOM menu. On this calculator that menu is currently blank.

Figure 15 Now we open the CATALOG by pressing the keys. The display in Figure 15 shows the result. We want to select the first option from the menu at the bottom. Therefore we press the key to move to Figure 16.

Figure 16 Figure 16 shows the start of the list of all items in the catalog. Note that this display was generated on a TI-86. The display on a TI-85 will be similar, though not identical (the "Asm(" line is not on a TI-85).

Figure 17 We could use the "page down" option to move through the alphabetic list of items in the catalog. It is a long list, and the value that we want appears close to the end of the list. Fortunately, the calculator allows us to jump around in the list. We do this by pressing the key for the first letter in our desired command. For us, to jump to close to the bottom of the list, we can press the key to select the letter "Z". This will cause the display to shift down to the start of the list items that begin with the letter "Z". (Again, the list on the TI-85 will be slightly different.)

Figure 18 In Figure 17 we jumped way down in the catalog list, but we need to move even further. Therefore, we press the key to move down a page of values. In Figure 18, we see more values, but not the one we want, namely . Therefore, we will keep pressing the key (about 6 times) until the display moves to the point where appears on the screen.

Figure 19 In Figure 19 we can see the desired . Note that it may not appear in the same position on your calculator. It is only important to have it on the screen. Also, in Figure 19, note that the small arrow at the extreme left of the screen is pointing to the top item in the list. We want to press the key enough times (5 times for the display in Figure 19) to move that selection arrow down to point to the option that we want, . All of this should produce Figure 20.

Figure 20 In Figure 20 we have the desired option on the screen, and we have the selection arrow pointing to that option. We start the process of placing the selected item into the CUSTOM menu by pressing the key to display the existing CUSTOM menu.

Figure 21 The existing CUSTOM menu is displayed a the bottom of the screen. We can place the selected catalog item into any of the spots on the CUSTOM menu by selecting that spot. In our case, we want to place the command into the first spot on the CUSTOM menu. Therefore, we will press the to select that spot and move to Figure 22.

Figure 22 Our command has been inserted into the CUSTOM menu. We will exit out of this process and move to demonstrate the work we have done. Press to close the bottom menu, and move to Figure 23.

Figure 23 Here we are back in the catalog. Press to leave this part of the catalog, and move to Figure 24.

Figure 24 Press to leave the catalog screen in Figure 24.
Now, we will press to clear the screen.

Figure 25 We construct the screen shown in Figure 25 as an example of a problem that involves fractions. If we want the answer to be shown as a fraction we will need to append the command. Fortunately, we now have that command in our CUSTOM menu. Therefore, the keys needed to move to Figure 26 are to open the CUSTOM menu, to select the desired command, and to perform the complete instruction.

Figure 26 Figure 26 shows the result of our efforts. Note that the CUSTOM menu remains open at the bottom of the screen. We could close it by using the EXIT key.

Figure 14	We can leave Figure 13 by pressing the keys to close first the MISC submenu and then the MATH menu. Then in Figure 14 we have pressed the key to display the CUSTOM menu. On this calculator that menu is currently blank.
Figure 15	Now we open the CATALOG by pressing the keys. The display in Figure 15 shows the result. We want to select the first option from the menu at the bottom. Therefore we press the key to move to Figure 16.
Figure 16	Figure 16 shows the start of the list of all items in the catalog. Note that this display was generated on a TI-86. The display on a TI-85 will be similar, though not identical (the "Asm(" line is not on a TI-85).
Figure 17	We could use the "page down" option to move through the alphabetic list of items in the catalog. It is a long list, and the value that we want appears close to the end of the list. Fortunately, the calculator allows us to jump around in the list. We do this by pressing the key for the first letter in our desired command. For us, to jump to close to the bottom of the list, we can press the key to select the letter "Z". This will cause the display to shift down to the start of the list items that begin with the letter "Z". (Again, the list on the TI-85 will be slightly different.)
Figure 18	In Figure 17 we jumped way down in the catalog list, but we need to move even further. Therefore, we press the key to move down a page of values. In Figure 18, we see more values, but not the one we want, namely . Therefore, we will keep pressing the key (about 6 times) until the display moves to the point where appears on the screen.
Figure 19	In Figure 19 we can see the desired . Note that it may not appear in the same position on your calculator. It is only important to have it on the screen. Also, in Figure 19, note that the small arrow at the extreme left of the screen is pointing to the top item in the list. We want to press the key enough times (5 times for the display in Figure 19) to move that selection arrow down to point to the option that we want, . All of this should produce Figure 20.
Figure 20	In Figure 20 we have the desired option on the screen, and we have the selection arrow pointing to that option. We start the process of placing the selected item into the CUSTOM menu by pressing the key to display the existing CUSTOM menu.
Figure 21	The existing CUSTOM menu is displayed a the bottom of the screen. We can place the selected catalog item into any of the spots on the CUSTOM menu by selecting that spot. In our case, we want to place the command into the first spot on the CUSTOM menu. Therefore, we will press the to select that spot and move to Figure 22.
Figure 22	Our command has been inserted into the CUSTOM menu. We will exit out of this process and move to demonstrate the work we have done. Press to close the bottom menu, and move to Figure 23.
Figure 23	Here we are back in the catalog. Press to leave this part of the catalog, and move to Figure 24.
Figure 24	Press to leave the catalog screen in Figure 24. Now, we will press to clear the screen.
Figure 25	We construct the screen shown in Figure 25 as an example of a problem that involves fractions. If we want the answer to be shown as a fraction we will need to append the command. Fortunately, we now have that command in our CUSTOM menu. Therefore, the keys needed to move to Figure 26 are to open the CUSTOM menu, to select the desired command, and to perform the complete instruction.
Figure 26	Figure 26 shows the result of our efforts. Note that the CUSTOM menu remains open at the bottom of the screen. We could close it by using the EXIT key.