Being Hopeless at Math is Costing Us Money

“I don’t do math—numbers give me a rash.” That’s a line I’ve used a lot, mostly because it’s true, but also because it gets me a laugh. Truth be told, most of us stink when it comes to doing math on the fly. That’s a problem, because being hopeless with math makes us putty in the hands of retailers.

Some rights reserved by MelvinSchlubman

Why is it socially acceptable to say that we’re bad at math, but not socially acceptable to say we’re bad at reading?

The truth is that it’s not okay to be hopeless with numbers. Here are three ways that our aversion to math costs us money: 

The number 9

Amazingly, 65 percent of all retail prices end in the number 9. Unconsciously, we’re charmed into believing the item is a bargain. Both Steve Jobs, who came up with the 99-cent app, and the guy in California who founded the 99-Cent’s Only stores have made millions off this human quirk. Retailers use 9 on purpose to lure us into buying something because they know we’ll assume it’s been discounted.

The good news is that simply being aware of the ways that retailers use the number 9 can break their spell over us. Whenever you see a price ending with a 9, stop and think about what’s going on.

Intentional confusion

It’s a trick retailers use all the time: A confused customer is more likely to opt for the higher price deal. An item marked 5/$4 prompts us to buy five items for $4, not 1 item for $.80, because it’s too confusing.

Which is the better deal: 33% off the regular price or 33 percent more product for the same price?

Studies show that most people go for the 33% more deal because they don’t know how to do the math and they simply guess. And they’re wrong. 33% off is the same as a 50% increase in the quantity. Let me show you:

If the regular price is $1 for 3 pounds, 33% off means you get 3 pounds for $.66 or $.22 per pound. If you opt for 33% more, you’ll get 4 pounds for $1 or $.25 per pound. The secret is to figure out the per unit price—per ounce, per quart, per pound. Now it’s easy to compare.

Price ignorance

In his book Priceless, author William Poundstone tells the story of the retailer Williams-Sonoma and a $279 bread maker.

Sales were lagging so they placed a nearly identical machine next to the $279 bread maker with a price tag of $429. Immediately sales doubled on the $279 model because it appeared to be 40 percent cheaper, and therefore a great deal.

The same tactic is in play when you see a big display in the supermarket with a sign that reads, “Special!” If you are not up on your prices, you’ll fall for every trick that retailers have up their sleeves to get us to spend more money.

Getting good with math, I’m discovering, starts with my attitude. That’s why I am never again going to tell myself or anyone else that I’m bad with math.

I’m doing brain calisthenics. And while forcing myself to figure out per unit prices on the fly is a good exercise, I’m learning that a pocket calculator is my friend, too.

How are you with math? Let’s discuss in the comments section below.

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24 replies
  1. peggy
    peggy says:

    i grew up in low tech/no tech times. we had to memorize times tables. i still remember the tables & have no difficulty doing math in my head. so sorry the kids today r getting cheated w/so-called new math. i have read it is called the dumbing down of America. sad.

  2. Kiyana
    Kiyana says:

    My very first job was in a supermarket as a cashier. So I learn this early. I am grateful for that. Even though im good at math, its a pain in the butt. Once you realize true Price per unit it’s worth it. Bad at math use a calculator. Try to shop when the store is not so crowded and you have some time to kill. Also look under the sales sticker on the shelf. Sometimes the item isn’t on sale, they just change the color of the sticker and put special so you think its on sale.

  3. Debbie G.
    Debbie G. says:

    Browsing the school supplies today at Target, I saw a notebook that had this message on it: “Dear Math, I am not a psychiatrist. Solve your own problems.”
    Really? And how is this going to encourage kids to learn?

  4. Anne
    Anne says:

    When I worked at JL Hudson in Detroit, many years ago, we had little girl’s dresses that sold for $3.99. They weren’t selling, we remarked them $4.00 (Hudson’s sale prices ended with even numbers), placed a ‘Special’ sign on them and they were almost gone by the end of the day. At 16 it was one of my first retail lessons. Like Myrna Bowman’s comment, I use the calculator on my phone, also the bar code scanner.

    • Bunny
      Bunny says:

      Anne, I am not up on ALL technology so I have to ask how the bar code scanner works &/or comes into play. Is it an ap?

  5. Myrna Bowman
    Myrna Bowman says:

    I use the handy dandy calculator on my phone…. made some interesting discoveries that way. My DH sometimes seems a little embarrassed when I have been known to announce in a slightly too loud voice how some of the “bargains” are a scam!

  6. Carol
    Carol says:

    Thanks for the encouragement. I had to laugh because as soon as you started the example of the percentages my eyes glazed over (actually my brain glazed over) because story problems have always boggled my mind. Thanks again. Carol

  7. Grace
    Grace says:

    With our penny disappearing in Canada I wonder how they are going to price things. The .99 will be gone. They will have to round it up. People always think when they get something for .99 they are getting a good deal rather than paying a buck for it. Those days will be history soon.

    • MilitaryMomx3
      MilitaryMomx3 says:

      If you’re paying with debit or credit card, it’s still going to be .99c
      Rounding up or down only comes into play when cash is being used.

  8. Elke
    Elke says:

    It always amazes me, how many cashiers can’t figure out out the correct change, when they enter the wrong amount tendered.
    Also a couple of weeks ago I wanted to buy shrimp at Walmart. I compared two different bags with different shrimp sizes and ounces. The unit prices didn’t look right, so I pulled out my calculator, and sure enough, the bag that was listed as the better per ouce price actually cost more per ounce. When I talked to the department manager, very nicely, since I figured they just put up the signs corporate gives them, he said my math was wrong. He treated me like I was an idiot. Even when I proved the discrepancy to him on my calculator, he never even apologized. But when I walked by later, they were changing out the signs. The lesson here is, when something doesn’t seem right, don’t just believe the unit price, but get out your calculator.

    • Yankee in Texas
      Yankee in Texas says:

      I recently made a purchase that totaled $11.16. I gave the cashier $21.25 so I would get a $10 bill back. She looked at me as if I had three heads then called a manager over because even with the cash register, she did not know how to make the correct change!!!

      • raine
        raine says:

        I work in a department store and I love math. In defense of the cashier, sometimes you just get brain locked. I’m sure you have never done anything like that, but it seems to be happening to me more frequently. 😉

    • D. Debord
      D. Debord says:

      You are exactly right! My guess is that you probably (not intentionally) made the manager feel like an idiot. But he should have been gracious and thanked you for calling it to management’s attention. That is what I would have done. Years ago when going through a popular drive thru, the order was coming up about $4.00 more than it should have. I am no math person by any means (was an art major in college), but I can do simple addition/subtraction. The employee repeated the order, which was right, but the total was wrong. She argued with me and said that is what the computer said and it was right. I didn’t have a calculator but still knew it was wrong. My family wanted me to pay it. I was real agitated by this point. I pulled into a parking space and went inside. Standing at the register and placing the order, I watched as the correct price came up. It was $4 less than I was being told at the drive thru, so I told them. The drive thru clerk was either skimming money off people or something was wrong with that register and she was just to ignorant to see it.

  9. Lucienne
    Lucienne says:

    When a store lists a product at, for example, 5 for $4, I will often deliberately buy only 1 or 2 just to show the store and myself I am not playing their game. If I’m required to buy the quantity posted in order to get their “special price,” and I don’t need that many, I walk away.

  10. penny50
    penny50 says:

    From the time I was a little girl, my mom always had me round up prices. If something was $1.95 she said it was $2.00. This is one trap I don’t fall into. I also worked with children with learning disabilities and we taught them all kinds of mental math solutions which has sharpened my math skills. My greatest pet peeve? I think I would pay more for gas just to go to a gas station that dropped that silly 345.9 per gallon. Call it $3.46 and I am your customer. This might have made sense when gas was 26.9 a gallon, but don’t try to save me 2 cents on a tank of gas!

    • Holly
      Holly says:

      Something else that is my pet peeve, esp with Walmart. I am trying to buy made in USA or America, as much as I can. Many stores are not putting where it is made, but they put ‘packaged by’ or some similiar term.

  11. Carol
    Carol says:

    I can drive myself crazy in the grocery stores doing this, because I refuse to be taken by the merchandisers. I’m sure I miss a bargain sometimes because I’m in a hurry, but typically, I compare everything by doing quick math! If it takes more than a few secondes in my head, I grab my cell and pull up the calculator. I stand in the toilet paper aisle and look at the square feet in packages of toilet paper, the merchandisers fluff up the paper and customers just see the ‘large’ rolls and think they are getting more for their money. I don’t typically purchase the stiff t/p, but I will make absolutely sure that I’m getting the best deal on the type I’m willing to use, then flush down the toilet!!! Eggs are also another item I absulutely must compare. Just recently I realized that jumbo eggs were the cheapest deal most of the time b/c of the weight. Most cartons don’t list the oz on eggs, but I found some. Now I know to pay attention to that. I have to really try hard not to get upset at my teenagers/husband when they pick up items for me, because they’re not quite as willing as I am to find the best deal! Saving money can become an addiction, if I let it!

  12. Terri
    Terri says:

    My math is fine, but I don’t like the way the stores don’t ‘play fair’ with unit pricing—within one category (e.g., canned food), some shelf labels will break the price down to “cents per ounce” while others will show “cents per pound” or “cents per mL”—this makes it impossible to quickly make a comparison, so I’m back to scribbling long division on the back of my shopping list, which I do often as I shop.

    • Kim Kindrew
      Kim Kindrew says:

      I just encountered this over the weekend when I was looking at agave nectar and trying to determine which was cheaper – one displayed the price per quart and the other displayed the price per ounce. Doing math on the fly just irritates me because I’m not in “math mode” – and I had to stand there and think “Ok, how many ounces ARE in a quart?”

    • penny50
      penny50 says:

      Sometimes it helps to remember a pints the same as a pound when they do this, so if one thing is per ounce and the other is per quart you can figure it out.’

      • Ruth Graper
        Ruth Graper says:

        I may be mistaken, but I don’t believe that’s accurate. A pint is a volume measure while a pound is a weight measurement. A pint of rocks certainly weighs more than a pint of feathers.

        What’s REALLY confusing is that there are two different kinds of ounces: a fluid ounce (fl. oz) is a measure of volume (such as 8 fluid ounces = 1 cup) and there’s a ounce (oz.) that indicates a measure of weight (such as 16 oz. in 1 lb.). It’s important to not confuse the two when trying to make the wisest purchases. I try to remember my calculator too!

      • penny50
        penny50 says:

        Sorry, I never came back to this. A fluid pint is the same as a pound. A pint of milk weighs a pound and a gallon weighs eight pounds.

    • Jen
      Jen says:

      This is probably my biggest pet peeve in the grocery store. Sometimes buying granola bars some are per ounce and some are per piece. Then each brand has a different amount in the box… some 6 some 8… I find myself having to find the ounces on the box(can,jar,package) then divide the price by # of ounces. My last job made me do lots of math on a daily basis so thankfully I’m not afraid of it anymore. 🙂


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