Hoarding stopped!

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A Danish market found an interesting way to limit hoarding of hand sanitizer.

  • How much are these costs in your currency?
  • What is the unit price on these bottles?
  • By how much (what percent) was the price increased?
  • Is this legal?

Weird and spooky puzzles for April Fool’s Day

This day is known for pranks and puzzles.  
Try one of these 4 activities on April Fools Day.

Ask students to analyze where I made my mistake


For members we have solutions. PerplexingProblem-solution.pdf

         CCSS: MP1, MP3, 4.OA, 5.G, 8.EE, 8.SP

Or baffle 'em with this Ghost Whisperer lesson.  They will think you are pulling one over on them until they figure out the math!

CCSS:  4.OA.4, 5.OA.1, HSA.CED.A.2, MP1, MP3, MP4, MP7, MP8

Pascal coloring and modular math

Pascal'sImagesIn this activity students have the opportunity to color as they investigate Pascal's triangle and the many useful patterns that it shows. The triangle is explored for patterns, coloring results, and motivation to learn more about modular arithmetic (clock math).

Data remaining … tricky

I checked my data usage for the month.  What do you notice and wonder?


  • What could my data plan be?
  • How much have I used?
  • How much will I have used by the end of the month?
  • Is this the best plan for me?

Is there much of a difference between 99.9% or 99.999%?

Use our present need for cleanliness to engage your students.

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Does it really matter whether you kill 99.9% of the bacteria or 99.999% of the germs?

In this 3-act activity we've asked students to consider whether these claims about these two wipes' efficacy really make a difference.  We've supplied students with a list of bacteria counts on various surfaces and asked them to calculate how much of a difference these two different percents make in wiping out germs.

This is an excellent opportunity to deal with repeating decimals.