Grade Levels: 3-5, 6-8

In these number line lesson ideas which are adaptable for grades 3-8, students play an online math game to practice identifying, comparing, and ordering fractions on a number line.

Lesson Plan Common Core State Standards Alignments

Students will:

  1. Develop understandings of numbers, ways of representing numbers, and number systems.
  2. Understand and represent commonly used fractions.
  3. Apply understandings of fractions as part of unit wholes and as locations on number lines.
  4. Compare and order fractions on a number line.


  • Computers with internet access for BrainPOP


This lesson plan uses a free online math game by NMSU called Pearl Diver. The game starts out with simple numbers but quickly introduces more complex concepts, including negative numbers, fractions, and decimals. In between rounds, students will take a break from diving and practice estimating skills as they prepare to slice some electric eel sushi. Pearl Diver teaches number properties, plotting numbers, visualizing quantity on the number line, ordering numbers, and using the number line as a visual model for mathematical operations.

To play, students must dive at the indicated spot on the number line, which will allow them to discover a pearl. Use the mouse to move left and right. Click to dive, then click repeatedly to open the shell. At each level, you must collect four pearls before time runs out. If you collide with the electric eel, you lose one of your divers. In the sushi bonus round, slice the eel as accurately as you can, according to the directions.

You can find additional lesson resources (including bonus activities) on the Math Snacks website.

Lesson Procedure:

  1. Here are some ideas for incorporating the Pearl Diver Game into your class' instruction:

  • Play the game as a whole class. Begin by playing the game yourself and using think-alouds to model mathematical practices. Then have student volunteers model various strategies and explain their thinking aloud, as well.
  • Play the game as part of your small group math instruction. You can differentiate for students' needs by selecting the appropriate level of game play for each group. Students can take turns coming up to the interactive whiteboard or computer and explain the move they think is correct. Ask other group members to use a hand signal to indicate whether or not they agree. Allow students to explore the game in pairs. Encourage students to problem solve together and take turns.
  • Provide time in class for students to play the game independently. Challenge students to advance through as many levels as possible in the allotted time. This is a great strategy to use after students have already had time to learn the basics of the game through group or partner play.
  • Encourage students to play the game at home. All of BrainPOP's GameUp resources can be access by students on any computer with internet access, with no login required. Students can also download the free Pearl Diver app and play on their mobile devices. You can offer extra credit to any student who completes the entire game and submits a screenshot to you.

Extension Activities:

Be sure to check out the other Math Games featured in GameUp!