Perform Calculations and Using the TINspire Attach Feature
Calculations can be used to make sense of the measurements that were taken. The TINspire Attach feature is a handy way to display the results of the calculations and measurements. You can use these tools to prove that two angles that form a linear pair are supplementary.
Follow these steps to perform a calculation:

Place some text for your calculation. Move your cursor to an open space, rightclick ([CTRL][MENU]), and choose Text. Type a+b and then press [ENTER].

Rightclick ([CTRL][MENU]) the text, choose Calculate, [CLICK] one of the angle measures, and then [CLICK] the other angle measure. Press [ENTER] to anchor the calculation.
See the second screen.

To lay down more text, rightclick, [CTRL][MENU]→Text. Press
(degree symbol). Press [ENTER] to anchor the text. Repeat two more times to give [+] and [=] a text box of their own.

Work right to left and attach each piece of the equation to the piece before it. Rightclick ([CTRL][MENU]) degree symbol, choose Attach, and [CLICK] the right side of the 180.
Now, rightclick 180 degrees and attach it to the = sign. Keep working backward until the equation is together in one attached piece! See the third screen.
The Graphs and the Geometry applications are approximate environments. As a result, you may occasionally get a calculation or result that is not what you expect. For example, if you move the point to form a 0˚ angle, TINspire displays 1.21Å6˚, instead of 0˚. This is scientific notation for the number 0.00000121, which is extremely close to zero. Consider these small noise values to be zero.