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Explain why a fraction a/b is equivalent to a fraction (n × a)/(n × b) by using visual fraction models, with attention to how the number and size of the parts differ even though the two fractions themselves are the same size. Use this principle to recognize and generate equivalent fractions.

📲Technology Required

Students will need a Mac or Windows computer with the Fish Lake game installed. A video can be a substitute for students who do not have access to one of these devices.


30 minutes


Begin with playing the Fish Lake game. A video of the section on crop rotation may be used by schools that don’t have Fish Lake installed. Give a presentation (included) on crop rotation. Watch a video on “What is one-half” and end the lesson with a presentation (included) on whether one-half is fair.


Play Fish Lake or watch video of game play

Even though you can use this lesson without playing the game, I urge you to install Fish Lake on your iPads, Mac or Windows computers. You can download it for free for computers. For iPads, email for a discount code and we’ll get back to you the same day. Seriously, even if you normally use Chromebook, it will be a nice break and your students will love it. We recommend letting them play for 15 minutes.

Play the game Fish Lake, (available to Growing Math schools, on iPad, Windows or Mac computers). If students do not have devices to access the game, students can watch a video here.

Slide presentation on crop rotation

Use this Google slides presentation to explain crop rotation as more than just being sure each farmer did her fair share of the work or had a fair share of the fields. It was good science.

Watch a short video: What is half ?

This short (1:40) video explains that one-half is two equal parts, with examples of one-half as a distance between two points or as a shape divided into two parts.

Slide presentation on one-half as fair

Use this Google slides presentation to show two halves are equal and that 2/4 = 1/2. Multiple examples of dividing something in half are given, from six blankets to half a deer. Students can also read the presentation and manipulate the examples on their own.

Half a deer


Fish Lake data reports are available for teachers to access after students have finished playing.  

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