If we were metric, the first hope would be that the manufacturer NOT keep using stupid sizes like 368 g. Due to conversion, when labelled in dual, one of the amount generally must be inconvenient. (I have seen products where both amounts are inconvenient; the manufacturer must be out to confuse.) How would you feel about 400 g for $3.09, or even 350 g for $2.70? I can work out in my head that either is a little under $0.80/100 g. (Correct answer is $0.771/100 g.) The model Uniform Unit Pricing Regulation by NIST and NCWM already allows unit pricing in either Customary or metric (few grocers use the metric option). Metric unit pricing is generally per liter or per 100 mL, per kilogram or 100 g.
The bigger question is why do you need to do this math in your head when we have unit pricing? The answer is the labels can't be read by people with normal vision. The pols are so happy to have unit pricing that they don't bother to require the labels be readable, only that they exist. So we have useless unit pricing while the politician has a brownie point on his scorecard for consumer sensitivity. That could be fixed. --- On Sun, 2/12/12, Paul Rittman <[email protected]> wrote: From: Paul Rittman <[email protected]> Subject: [USMA:51457] Calculating prices with grams and ounces To: "U.S. Metric Association" <[email protected]> Date: Sunday, February 12, 2012, 12:22 AM The last few times I went shopping for breakfast cereal, I tried to compare the prices of various cereals on a per-ounce or –gram basis. Tonight, one cereal I bought was $2.84, and the package said it weighed 13 ounces or 368 grams. Calculating the price per ounce seems to be much easier than calculating the per gram price. I was able to quickly see that it costs about 20 cents an ounce (quite a bit cheaper than most other cereals) by multiplying 13 x 2, and then adding a zero. I then decided to try to get the cost per gram, but decided not to even try to put 368 into 284. After a similar experience shopping last week, I saw that 20 cents an ounce was roughly equal to 0.7 cents a gram. I’m not sure that I want to multiply the number of grams by 7, and then move the decimal. Another option I thought of was to take a tenth of the gram total, and then subtract it 3 times (from that total), to see if the price was at 0.7 cents a gram or lower. Still, it seemed like a lot more work. I know folks can say it’s just that I’ve just gotten used to imperial measurements, but it does seem a lot easier to me to use when shopping, that’s for sure. Now I know that if our country were officially metric only, the supermarkets would be posting the prices in metric terms on the labels on the shelves, but honestly I don’t like to use them because the writing is so small (even when they are given with imperial units). OK now—is this simply a math process that I’ve forgotten about, that will allow me to calculate as easily with grams? Or is this simply an area where working with imperial units is easier? I am well aware of the various advantages of the metric system…. is this just an example of no system being perfect?
