Equivalent fractions: watch the teacher re-cut a GeoGebra bar while the shading stays put

Grade 3 (Year 4, age 8 to 9) · 45 min · Teacher device and projector

The teacher projects a GeoGebra applet showing a bar with three quarters shaded and a slider that doubles, triples and quadruples the number of equal parts. As the teacher drags it, the bar is re-cut into 8, 12 and 16 parts while the shaded amount stays exactly where it was, and the fraction beside it changes from 3/4 to 6/8, 9/12 and 12/16. The teacher repeats this with 1/2 and 1/3, pausing to ask what the class notices about the numerators and denominators, and children answer out loud and on mini whiteboards. They finish by writing three fraction families in their books and a sentence on why the shaded amount never changed.

Why this is Passive Amplify

Children watch as the teacher drags the slider, and their answers go on mini whiteboards and in books, so they are receiving content through the technology. The task is the fraction-wall demonstration the teacher would have drawn on the board, and GeoGebra adds continuous re-cutting of the same bar, so children see the parts multiply while the shaded amount stays fixed, for any fraction the teacher chooses and as often as the class needs.

Compared with

The teacher drawing fraction-wall rows on the whiteboard, one under another, and shading 3/4, 6/8 and 9/12.

Watch out

If children dragged the slider on their own tablets and recorded what they found, they would be manipulating the content and the lesson would be Interactive.

Tools: GeoGebra Nine ideas for your own version in Generate

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Equivalent fractions: watch the teacher re-cut a GeoGebra bar while the shading stays put.

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