Perform Calculations in GeoMaster on the TI84 Plus
GeoMaster on the TI84 Plus calculator is capable of adding and subtracting like measures that GeoMaster found using the Distance/Length, Area, or Angle tools in the MEAS menu. It can, for example, add two area measures; it cannot add unlike measures such as an area measure and an angle measure. GeoMaster cannot multiply, divide, or square a number.
So if you want to use GeoMaster to verify the Pythagorean Theorem, you’re out of luck.
To add or subtract like measures found by the Distance/Length, Area, or Angle tool, follow these steps:

Press [GRAPH][ZOOM][4] to select the Calculate tool from the MEAS menu.
The tool you selected appears in the upperright corner of the screen.

Use the arrow keys to move the cursor to the first measurement and press [ENTER] to select that measure.
Place the cursor at the beginning of a measurement to select it. After you press [ENTER], the measurement is highlighted.

Press [+] if you want to add another measurement to the measure selected in Step 2; press [–] if you want to subtract.

Use the arrow keys to move the cursor to the next measurement in your addition or subtraction problem and press [ENTER].

Repeat Steps 3 and 4 to add and/or subtract more measurements.
GeoMaster allows you to add and/or subtract up to a maximum of six measurements.

Press
to find the answer to the addition and/or subtraction of measurements.
This step is not necessary if you added and/or subtracted six measurements. In this case, GeoMaster automatically calculates the answer.
The calculated answer, preceded by an equal sign, appears on the screen near the location of the cursor.

Use the arrow keys to move the answer to a better location and press [ENTER] to anchor that location. Press [ENTER] again or move the cursor.
After adding or subtracting measurements, the Calculate tool remains active until you deactivate it. So if you want to add or subtract more measures, repeat Steps 2 through 7. When you are finished using the tool, deactivate it by pressing [CLEAR] or by selecting another menu item.
The Calculate tool will not allow you to use a calculated answer in an addition and/or subtraction problem involving measurements. A calculated answer is preceded by an equal sign.