# Symbols

In the general settings of the exercise, the symbols tab is available. This symbols list is used to help AlgebraKiT interpret your question definitions.

##### Example

With a simple algebra task definition of $4m$, the author could either refer to the variable $m$ or to the unit meter written as $m$.

As the intended behavior of these two options differ (is a student allowed to write $400 cm$ as intermediate step?), AlgebraKiT needs to understand the meaning of the symbols used in your questions.

To limit the authoring overhead as much as possible, AlgebraKiT will alert you whenever a symbol definition is not clear, and will make an educated guess for these symbols. In such case, you will get a popup like this:

Make sure to verify this educated guess, as it impacts the resulting behavior of your exercise. When saving your exercise, the symbol definitions are also saved.

When the educated guess is correct, you can simply click Confirm and add to symbols list and no other input is required from your side.

By clicking Close you ignore the symbol definition. Your exercise might NOT work outside the authoring environment!

In case one or more interpretations are not correct, you have to update the interpretations. The easiest way is to click Confirm and add to symbols list. Next, go to the symbols tab and update the interpretations to reflect the correct settings. In our case, the $m$ was intended as variable, so we update the setting to be interpreted as variable:

The next run, AlgebraKiT will use the correct interpretations.

There are some advanced mechanisms available:

Euler’s constant

When authoring an exercise, it might be the case that you want to use the Euler $e$ instead of the variable $e$, or that you want to use both next to each other in the exercise. Below, both options are explained:

Using the Euler $e$:

Go to the Symbols tab at the top of the exercise, and add $e$ as a constant.

You can now author the question as you intended and use the textual e where ever you want to refer to the Euler $e$.

Using the Euler $e$ and variable $e$ in the same exercise:

Go to the Symbols tab at the top of the exercise, and add $e$ as a multiple. Next, add two entries. One for constant, and one for variable. Give both entries a name. For example:

You can now author the question as you intended, except you have to use the names you just created to refer to the specific item. So you use $eEul$ if you want to refer to the Euler $e$ and $eVar$ if you want to refer to the variable $e$.

The student can still write $e$ to refer to both inputs, and AlgebraKiT will match which of the two $e$ definitions is intended.

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Duplicate symbol definitions

When authoring an exercise, it might be the case that you want to use the multiple definitions of the same symbol next to each other in the exercise.

Let us look at an example using the physics formula $W=m \times g$ where $W$ is the weight, $m$ the mass of the object, and $g$ gravitational acceleration.

In the above exercise, the symbols $m$ and $g$ are used with multiple definitions:

• $m$ for the variable representing mass and the unit meter
• $g$ for the variable representing gravity and the unit gram

Although the unit gram might not be directly used in the exercise definition, it is included in the context, since the unit $kg$ is used, and thus AlgebraKiT automatically derives that $g$ might also be used as a unit of weight.

For both symbols, we can define that they have multiple definitions, such that AlgebraKiT understands the exercise definition and is able to generate the worked solution and process student input automatically.

To enable this functionality, go to the Symbols tab at the top of the exercise, and add your symbol (in our example $m$) as a multiple. Next, add the required entries. In our example, one for unit, and one for variable. Give your entries a name. For example:

You can now author the question as you intended, except you have to use the names you just created to refer to the specific symbol. So in our example, we use $mUnit$ to refer to the unit meter and $mVar$ to refer to the variable $m$ for mass.

The student can still write $m$ to refer to both inputs, and AlgebraKiT will match which of the two $m$ definitions is intended.

The same applies for symbol $g$, which is left as an exercise for the reader (or refer to this AlgebraKiT Library example where the question is available for your reference).