Tag: math around us

  • Positive, Negative and Zero Numbers — And Dove Body Wash!

    Positive, Negative and Zero Numbers — And Dove Body Wash!

    Every real number can be classified as positive, negative or zero. And you can use bath products to teach this!

    We attended the Dad 2.0 Summit a couple of weeks ago. Husband scored some really neat Dove Men Care products. I asked for a set too.

    I was lathering myself up in the shower and starting to smell rather manly. I wondered if there was an equivalent Dove product that had a super intense, feminine smell.

    Which made me think of the number line.

    Negative, Positive and Zero.

    People often ask me about zero — is it positive or negative?

    Every number is is either positive, negative or zero. Those are the three possible “states” — and each number is exactly one of them.

    That’s why we sometimes use the term “non-negative.” Non-negative doesn’t mean positive. It means a number that is either positive or zero.

    It’s a subtle difference but super important.

    But teaching it with Dove Body Wash? Really?

    Yes!

    There are three general marketing tactics for body wash — male, female and “neutral.”

    This can correspond with the positive, negative and zero of the numbers!

    (Of course which you choose as positive or negative depends on you — my favorite person happens to be my husband — a male — so I picked for men as the positive numbers in my graph.)

    You can even reinforce the math language.

    Suppose you’re in the shower and you notice you’re out of body wash. You can call to your child and ask, “Will you bring me some Dove Men Care body wash.”

    Which is like saying, “Bring me some positive body wash.”

    Or you can say, “Please bring me some body wash — anything as long as it’s not that girly-smelling Dove Purely Pampering stuff your mom uses!”

    Which is equivalent to saying, “I want the non-negative body wash.”

    How about it?

    What do you have in your shower or tub that you can illustrate positive, negative and zero with? Will you give it a shot?

    Share your thoughts in the comments or on twitter/x. And don’t forget to pin this on Pinterest!

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  • How to Find the Cheapest Price per Unit

    How to Find the Cheapest Price per Unit

    I’m heading to the Dad 2.0 Summit tomorrow so last week I ordered more of my super cool playing card business cards.

    Business Cards - using playing cards!

    I had to decide how many decks to buy — and I wanted to pay the cheapest price per deck.

    I had to work within my constraints.

    I had only one and a half weeks to get them in. And less than $50 budgeted for them.

    And I needed at least 100 of them.

    These playing card business cards aren’t cheap — about $10 per deck of 54, plus shipping costs. But I love them.

    I was willing to pay the premium price.

    But I still wanted to get the cheapest price of the premium price that I could!

    So I did the math!

    Here’s a screenshot of the price structure from YourPlayingCards.com:

    Pricing structure breakdown for playing-card business cards.

    Since my budget was $50, I had to go with four or fewer decks.

    I started looking at the per-deck cost of shipping.

    • If you order 1 deck, the cost is $4/deck to ship it.
    • If you order 2 decks, the cost is $3/deck.
    • If you order 3 decks, shipping is $3.33/deck.
    • And getting 4 decks cost $2.50/deck for shipping.

    Four decks is the winner — or is it?

    Four decks would be right at $50 — and give me 216 cards. But if I went even more under budget with 2 decks — my total comes to $26.

    Since I only plan on using 50-100 cards at this conference, two decks would be fine.

    “But that’s not the cheapest price per unit,” you say?

    The cheapest price per unit sometimes isn’t the cheapest!

    If I buy two decks now, and two decks later, it costs me $52 ($26 + $26). But if I buy four decks now it only costs me $50.

    Even though I want to get the cheapest price per unit, I’m focused on the the “out the door” cost, too.

    What I really need right now is two decks. And the “out the door” cost on those is $26. Just about half of the $50.

    Which means that, for now, two decks is the cheapest for what I need!

    How about you?

    What have you found is cheaper in theory but not in reality? Share it in the comments or on twitter/x. And don’t forget to pin this on Pinterest!

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  • Surgery Day Math

    Surgery Day Math

    I’m off to surgery in 60 minutes.

    I haven’t eaten since 12am.

    They’ll measure the anesthetic in cubic centimeters.

    They’ll use 2 holes to do the procedure.

    They’ll put a range of motion knee brace on me.

    I’ll come back in 7 days.

    Even on surgery day, everyone’s doing math!

    This article is a part of the 50 Word Friday series. Learn more about this strange, limited writing style here…

    Share your thoughts in the comments or on twitter/x.

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  • Science Shows Math Too!

    Science Shows Math Too!

    The 2012 STEMie Award competition is open to all schools and homeschools in the United States and is sponsored by McGraw-Hill. The deadline to enter has passed.


    I work hard to convince you to see math around you — in even the most obscure things like lipstick, tattoos and cheese.

    You may not have noticed that none of these, or any other articles I’ve written about the math you can find around us, contain science. At least not in the textbook sense.

    But one of the fastest and easiest ways to see math around you is through science. So it’s kinda ridiculous that I haven’t really talked about it.

    My Nephew is Learning Science

    I received an e-mail from my dad today encouraging me to vote for my nephew’s school’s science program, SMORE. Turns out, they’re in competition to win a grant from McGraw-Hill, and 30% of their score comes from online voting for their video. (BTW, that’s math too!)

    Knowing that he’ll be learning a lot of math when he’s learning the science, I’m supporting his school.

    Make sure to support your kids and schools in science — they’re doing math!

    Share your thoughts in the comments.

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