Upcyled Juice Lids Teach Integer Operations

Juice lids help teach signed numbers operations!

Click to enlarge: Red (dark) lids = negative, silver lids = positive

I've used the "chip method" to teach adding signed integers (the whole numbers and "negative whole" numbers) and to teach prime factorization, but I've never used them to teach multiplying and dividing integers. Until today. Thanks to my beautiful ride to school today, this method popped in my head on the drive. I hope my Elementary Algebra students found this helpful!

Note: These are the metal lids from the top of frozen juice concentrate.  

Click here for tips on another  good lid source!

The example above shows that every pair of reds (negatives) when multiplied will equal a silver (positive). In the numerator:

(-3)(-2) = (red)(red) = silver

and in the denominator:

(-1)(-3) = (red)(red)  = silver

Then

silver/silver = silver (positive)

For those students (like me) who need manipulatives, who are better when they can touch something that can be so abstract, I think the magnet lids are the way to go! Again, this is why I collect all sorts of lids and caps... imagine the possibilities in ANY math classroom or home.