In this lesson, we’ll explain how to replace variables, also with the plug-in method, to solve Math problems with the GED calculator TI-30 XS. This lesson is included in our free online GED classes.

In the second part of the GED Math exam, you can use a scientific calculator, but it has to be the TI-30 XS.

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In some Math questions, letters stand for numbers. These letters represent unknown values and are called variables.

When we replace letters with a given number, we can perform the usual Math operations. This process is known as evaluating expressions.

Here is a simple example.

Calculate:

1/2a+33

when a=184.

Is it: Option one: 125?

Or Option two: 97?

So, you need to replace the letter “a” with the number 184 and then calculate the total value.

So, we need to input the following expression:

½ times 184 plus 33.

Let us use our TI 30XS to perform this calculation.

Press the fraction sign and type 1 in the upper box, then use the arrow to navigate to the lower box and press 2. Press enter to finish editing this fraction. Our screen shows the ½ fraction, now press the multiplication sign and then type 184. Then punch the plus sign for addition and type 33, and finally press the enter sign to see the result.

It’s 125.

So, option 1 is correct.

Next lesson: How to replace variables using the plug-in method