Model expressions and equations on a number line with positive and negative jumps.
Print out positive and negative jumps, and then place them standing up on the number line to build expressions. Create two expressions that both start at zero and end at the same place to form an equation. This is a powerful hands-on modeling tool to help students bridge the gap between modeling situations and symbolic representations.
Teachers: I've included two worksheets (pdf files) that students can use use along with this manipulative. The worksheets include examples of how to use the tool.
Here are the Common Core standards associated with this manipulative:
K.OA.2, 1.OA.1, K.OA.2
2.MD.6, 6.NS.5 and 6.NS.6, 6.EE.2 and 6.EE.6
I've include the SketchUp source files (in the zip archive).
If you want both positive and negative sides on your the number line, print out these parts and snap together:
If you want only the positive side, then print out these parts:
I don't have a dual extrusion printer, so I obtained the black numbers and ticks on the white background by starting out with white filament, and then pausing at 4.4mm and switching to black filament. Looking forward to learning how to make dual-extrusion capable files.
I printed positive jumps green and negative jumps red, but the color obviously doesn't matter. Here I got the black numbers on the colored background by switching filament at 3.8mm.
I grouped the jumps into sets of small positive, large positive, small negative and large negative. There is also a "negative zero" jump as a separate file if you want to model subtracting a zero.
I've included the source files (SketchUp), so one can easily break out individual jumps as needed. Let me know if it would be preferable to have these already broken out into separate files.
I've included a couple of worksheets as examples of math problems that one might use with this manipulative. The worksheets have examples at the top which might be helpful.