Math is Hard

I know math isn’t everyone’s thing. But if you’re a store, and you’ve got a box on the price tag for ‘unit price’, you should know what it means. At least make an effort at some type of calculation. Just putting the price of the item over there again makes it seem like you aren’t even trying. 

I know I’ve ranted on this topic before, but it’s a pervasive, persistent problem. I find examples of this every time I’m in a grocery store. 

Part of stretching a grocery budget is comparison shopping, and without unit prices (or with deceptive unit prices, or changes in ‘unit’ choices) that becomes more difficult. I have no problem pulling a calculator out to figure out what I need to know, but not everyone has my brand of commitment to knowing the answer to this particular problem. 

Maybe I should start writing the correct unit prices on tags? Guerrilla Grocery Correction–coming to a store near you! 


Happy Ad Wednesday

This week presents with math problems. Skip on down to the deals and you’ll be a-ok to get on with your bad self and get to the shopping. Read on if you want some of the sort of granular analysis I apply to the grocery puzzles I face weekly.

I’ve mentioned Avocado Math. This week introduces Berry Math and Kale Math

Kale Math is because of my problem with the units kale is sold in–a ‘bunch’ is just an inherently non-specific amount.  Why can’t they just weigh it?  Maybe I’ll call some produce folks and ask, since I really don’t want to buy the amount of kale required to sort out which ‘bunch’ is the best unit price. Stay tuned for that post, which I’ll likely pair with Avocado Math because I’m very interested in that as well. Or possibly I just feel I can eat the amount of guacamole that would result without guilt if it’s for Cheepie and Math.  Either way, it’s a sacrifice for the greater good.

For now, organic kale is 98c-$1.50 and I’m just listing them all because how do I know which bunch is best?

Berry Math is simpler, and I care about it because they freeze wonderfully (put in freezer, done) and are useful in smoothies. So here’s the deal this week:


Randalls, 18 oz., $5           Sprouts, 5.6 oz., $1.98 ea

Our units are both ounces, so we can just divide to sort this out:

$5.00/18 oz= 27.78c/oz         $1.98/5.6oz=35.3c/oz

Randalls is the winner here. You’re paying decently less if you wait and stock up on Friday at Randalls.


Randalls, 18 oz., $5          HEB, pint, $1.88 ea

We have a unit problem here: ounces and pints. Turns out, if you Google, a good estimate for the weight of a dry pint of blueberries is 12oz.  That makes the Randalls deal TERRIBLE.

$5.00/18oz=27.78c/oz             $1.88/12oz= 15.6c/oz    

Buy blueberries at HEB.  Both berries can be tossed in a Ziploc and frozen after washing.

Last, a note on the Fiesta pork special:  Sirloin is not the same as loin. Most pork chops that people usually buy are loin:sometimes bone-in, sometimes not, but loin is the most common.  Sirloin is a tougher portion of the pig, and isn’t going to cook up the same if you’ve got a favorite pork chop recipe. This is certainly the price to get some and give them a try if your family likes pork, but be aware that ‘grill three minutes on each side and make a dijon sauce’ isn’t going to work as well with these.


pork sirloin chops      99c/lb (Fiesta limit)

Tyson whole fryer      99c/lb (Fiesta limit)

Bumblebee Chunk light tuna      69c/ea  (10c cheaper than Randalls)

Del Monte spaghetti sauce, 24 oz can      89c/ea


Sanderson Farms whole fryers       99c/lb

Safeway chicken drumsticks or thighs      99c/lb

Mt. Olive pickes       B1G1  (usually these are $2-$4, and have a long shelf life)

$5 Friday

18 oz blackberries (see note above, dont get blueberries by mistake!)

Family Size Cheese pizza (take and bake, in the refrigerated case)


blackberries, 5.6 oz          $1.98/ea (if you can’t wait until Fri)

strawberries, 1 lb.         $1.25/ea (DD)

Red Delicious apples     48c/lb  (DD)

pineapples      $1.98/ea (C15)

organic Braeburn apples      98c/lb  (DD)

bulk brown rice, short orlong grain      69c/lb

organic kale            $1.50/bunch  (DD)

last week’s post for the deals that end today


Fuji apples     77c/lb  (DD)

blueberries     $1.88/pint

organic Texas spinach       $1.48/bunch  (DD)

Rio Grande oranges, 4lb      $1.98/sack

HCF drumsticks or thighs      $1/lb


local curly kale bunch      $1.50/ea  (DD)

Whole Foods:

organic kale bunch                    98c/ea  (DD)

All the stores seem a bit thin this week. But then there’s this:

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Randalls came up with a variation I haven’t seen before this week–79c each when you buy 8, on several items ranging from tuna to Gatorade. The items are some of my pantry staples, so look at what they’ve got and maybe you’ll want to stock up.

It’s still Randalls, so don’t get distracted and do all your shopping there, but I’ll be getting noodles, tomatoes and tuna. Eldest will also require brownie mix.

Large Image

Happy shopping everyone. If you’ve got suggestions, or find great items, let me know here, or on Facebook or Twitter. 

Cheep Cheep!

Unit Pricing: the Good, the Bad and the Half-Cracked

Monday’s Grocery Theory post here, sneaking in just over the wire. So far Grocery Theory posts have introduced a ranking of Austin grocery stores, methods of storing when stocking up, the types of shopping we do, meat, and weekly planning.

Today’s topic: Unit Pricing.

You know what I’m talking about here. It’s that other number, usually on the shelf tag telling you how much your item will be.  Many people never take a look at that other number, some people will look at it to compare if they are buying an item they’ve got zero brand loyalty to follow, and others, well, others are always looking at them and doing the math.

It’s often surprising.  In a perfect store, these numbers should help you comparison shop, by letting you know this toothpaste is $X per ounce, and that one is $Y per ounce (don’t worry, algebra haters, we’re not going to keep using numbers where letters should be!).

Or say, eggs.  Eggs should be easy.  You’d like to know how much each egg is in the dozen you’re buying, compared to that dozen over there, or even compared to the 18-count over there.  Heck, go crazy and compare it to that big 2 1/2 dozen thing people only buy at Easter, why not?  It’s normal to expect the unit price to be per egg, and you’d have a second expectation of the price per egg being cheaper for the larger sizes.

Expecting something and finding it aren’t the same.

How the Unit Pricing Labels in Stores Can Trick You into Spending More

When is the last time you paid $34.69 for a dozen eggs?  Yeah, me neither.  This photo, taken by David S. Read and posted to his blog, is a great example of completely unhelpful, non-coherent unit pricing.  You look at the first one, and you realize, someone multiplied the actual price of a dozen eggs by 12.  That pattern works for a bit, ( with a hiccup for that 6-count at the top right, where they’re inexplicably multiplying by 2. because 6 is half a dozen?) but then there’s an 18 count egg carton, and they multiply that by 8 to get the unit price.  NICE!  But also deeply wrong.  Then it ends with unit prices per dozen, which seems to be the what they can handle even if it’s not a useful unit tool, because they got all of those right.  A dozen eggs cost as much as a dozen.  That’s a safe bet.

I saw this photo, and read his post, and was relieved.  For years I’ve thought I was the only person looking at unit prices, and now I know I’m not alone.  I thought I must be, because I’ve spent hours of my life in the toilet paper aisle (yes, this is a first-world problem I am having in the toilet paper AISLE.   I have multiple stores with aisles of tush-wiping paper.  I would be happier if there was one tp and I could just buy it and get on with my bad self!  Or if we all agreed to use leaves), trying to figure out what to buy.  At some point I’ll make a composite photo like the egg one, but toilet paper unit prices come in: sheets, sq. ft., sq. in., 1000 sheets, cm², and m².  Have you ever stood there trying to figure out how many square feet per roll, so you could make an even comparison?  I have, and it’s not simple.  You’ve got to look at the size of the sheet, get the area, multiply that by the number of sheets, and multiply by that, and then convert sq. inches to to sq. ft. so you can compare it to cm² …yeah.  That’s where even I stop and buy the one that seems cheapest per reasonably sized roll. I hate myself when I do that.

But it’s not just eggs and toilet paper.  I’m surprised all the time about the correct math that shows it’s cheaper to buy the smaller size of something rather than the larger (often, laundry detergent, soup, cereal), and by the wrong math demonstrated on the tags.   Listen, if something that’s 8 ounces is 99¢, then it’s safe to say it’s not $1.89 per ounce.

I feel like Common Core is trying to address this problem, with all of the estimates, and writing about how you got your answer.  But honestly, if you as a shopper don’t see this, your shopping isn’t doing right by your grocery budget. Knowing how unit prices work is one of the great ways to save.  The only thing that stops me from buying the cheapest thing per unit is brand loyalty, and I have very few of those (Hell-O Velveeta for queso!).

Unit prices, when correct, can help you. I use them all the time, especially when buying cheese, canned goods, rice, and beans.  You can too.  You don’t need a calculator, just look. In most cases, they’re right. If something seems hinky–pull up the calculator on your smart phone and see if your intuition is right.  That photo up there is an extravagant example of unit pricing being crazy.  If you saw a sticker that said unit price was over $20 for a box of macaroni and cheese, you’d stop, right?  In some terrible stores (HEB, you took unit prices OFF your eggs at Wm Cannon/S. 1st!) you don’t even have unit prices.  Texas doesn’t require unit pricing, and just last week I noticed that they’ve been removed in some areas, prompting my post.

How to Calculate Unit Price

Whenever you want to know the unit price? Look at what you’re buying. How much is it? Enter that into the calculator. Then, how big is it? This is the fiddly bit–if you are looking at a unit price, you want to match that, so if it’s per ounce (oz) that’s your number.  Then you divide by that number. That’s your Unit Price, which is Dollars per Amount of Stuff.

Comparing efficiently means matching units, so if you want to buy pasta, and you’re looking at different brands that are all 1lb each? Each one should have a label saying how much it costs, and also how much per lb. or per oz.  If some are not labeled that way,but instead are ‘per serving’ or per 8 oz., that’s when you need to start getting cranky.

Unit pricing is one of the best tools a grocery shopper has. If stores corrupt it, or don’t use it, it’s to the shoppers detriment. I encourage everyone to look at those unit prices. If the math doesn’t work, note it, and tell store management if possible. If there isn’t a unit price, and you want one, let them know that, too.  Use your grocery dollars in the very best way you can!