Create a randomized fraction addition question

In this tutorial, you'll learn how to create a randomized math question using variables and computed answers.

Outcome: By the end of this tutorial, you will create a fraction addition question whose fractions are generated randomly each time a student attempts the exercise.

Before you begin

Prerequisites 

• You should be comfortable working with basic fractions and have access to a LearningLemur-enabled course
• You should have completed Create an open-answer fraction addition question

Requirements

• A teacher account with permission to create questions in LearningLemur, accessed through learninglemur.com or your LMS

Step 0 — Create or open a quiz

Why: LearningLemur organises all questions inside quizzes, so creating a quiz first provides the workspace where you will add and manage your questions.

1. Open LearningLemur
2. Open an existing quiz or create a new one

Checkpoint: You should now see the quiz workspace with options to add questions.

Step 1 — Add a new question

Why: LearningLemur allows you to create questions either manually or with the help of AI. In this tutorial, we will create the question manually to understand how the editor works.

1. Inside the quiz, click Add question
2. In the creation dialog, choose Manually
3. Select the Open answer question

This question type allows students to enter a mathematical expression using the math editor.

Checkpoint: You should see the Open Answer question editor, including fields for the title, statement, and answers.

Step 2 — Write the question statement

Why: The statement explains the problem students must solve. It will use variables instead of fixed values.

1. Enter a Question title, for example: Sum of two random fractions
2. In the Question statement, write the exercise text (these letters will later be defined as random variables)

You can use the MathType editor to format fractions using mathematical notation.

Checkpoint: The question statement should display the variables inside the fraction expression.

Step 3 — Define the random variables

Why: Random variables allow LearningLemur to generate a different version of the question each time.

1. Open Question settings
2. Locate the Random variables section
3. Add the following variables:

These variables will define the numerators and denominators of the two fractions.

Checkpoint: The variables should appear listed in the Random variables section.

Step 4 — Define the random expression (solution)

Why: Instead of defining the answer directly, LearningLemur allows you to compute the correct result using a random expression based on the generated variables.

1. In the Random variables panel, go to Random expressions
2. Click Add random expression
3. Create the following expression:

This expression calculates the result of the fraction addition using the random values. LearningLemur automatically evaluates this expression and simplifies the result using the mathematical engine.

Checkpoint: The variable sol should appear under Random expressions.

Step 5 — Define the correct answer

Why: LearningLemur needs to know the expected solution in order to evaluate student responses.

1. Scroll to the Answers section
2. In the first answer field, enter the expression #sol
3. Mark this answer as a Correct answer

Using #sol ensures the answer corresponds to the computed result of the random expression. LearningLemur will compare student responses with this expression using the mathematical evaluation engine.

Checkpoint: You should see the answer marked as a correct answer (100%).

Step 6 — Configure the evaluation

Why: Evaluation options determine how student answers are compared with the correct solution.

1. Click Edit in the Evaluation options section
2. Ensure Mathematically equal is selected

This allows LearningLemur to accept equivalent expressions.

Checkpoint: The evaluation summary should display something similar to:

Step 7 — Preview the question

Why: Previewing allows you to verify that the question generates different values and that LearningLemur evaluates the corresponding result correctly each time.

1. Click Preview question
2. Note the fraction values generated in the question
3. Use Fill with correct answer, or calculate the result manually from the values shown
4. Submit the answer
5. Click Regenerate question and compare the newly generated values with the previous ones

Checkpoint: Each preview can yield different fractions, and the correct answer is evaluated based on the values shown in that preview.

You're done

You have created your first randomized math question in LearningLemur. You learned how to:

• Define random variables
• Compute answers dynamically
• Evaluate expressions based on generated values

Next, you can continue learning with the following tutorials:

• Create an area question with units
• Create a randomized geometry question
• Configure partial scoring for units

Troubleshooting

The same values always appear in the preview

Check that the question uses random variables in the statement and that the correct answer is based on a random expression, not on a fixed value.

The correct answer is marked as incorrect

Check that:

• The answer rule points to the computed expression (for example, #sol)
• The random expression is written correctly
• The evaluation option is set to Mathematically equal, not Literally equal

The question shows variables instead of numbers

Check that the variables used in the statement are defined in the Random variables section, and you are preceding them in the statement with the # symbol.