Math has never been my strong point. In my work, I rarely have problems that can’t be solved with the help of a construction calculator, or a phone call to a more mathematically fluent friend. Fortunately, most of the time I’m calculating simple linear or square footage.

A few years ago, I went to estimate a whole house paint job. To do this, I need to know the square footage total of all surfaces to be covered. I charge a price per foot, and also use the total square feet to estimate the number of gallons of paint needed. My way is to measure the area of the floor of each room. From this measurement, I can then find the sum of the square footage of the walls:

If the footprint of a room is 10′ x 10′ and the walls are 8′ high, each wall will be 80 square feet. If I multiply that by 4, I have 320 square feet of wall space to be painted. If the ceiling is included, I will add 100 (because if the floor is 10′ x 10′ the ceiling is 100 square feet). I now have 420 square feet of wall and ceiling to be painted. Of course it’s not quite that simple because I have to allow for doors, windows and whatever else is subtracted from coverage. I will go room by room taking measurements.

Are your eyes glazing over yet? Me too – it’s a tiresome process. Here’s where it gets better…

I went through my calculations as quickly as I dared, not wanting to stay any longer than absolutely necessary. I don’t charge for estimates, and I don’t like loitering in potential customers homes scratching my head at numbers. I don’t use estimating programs/apps, and I don’t necessarily trust myself with calculators. I know it’s old school – but I trust a ruler, pencil, paper and previous experience. I announced my number and left.

A couple days later I got an email from the homeowner. It stated that my estimate was for twice the square footage of the actual house: “…Can we assume that your square footage estimate was off by half so can we maybe negotiate your price based on that?”

My first reaction was that I had made an colossal mistake in my arithmetic. I did that a lot in school. But when I gave my estimate at the house, my number “felt” right. I had done jobs of this size before. Looking over my numbers again and again, I came to understand that the homeowner was going by the square footage of the *footprint* of the house.

I emailed back and showed step by step how I arrived at my estimate, but I did not hear back. I imagine they were pretty embarrassed at trying to call me out on such an huge error.

I try to encourage homeowners to get more than one estimate. Most (if not all) contractors do this for free. And these days, I always ask if they have some idea of what the job is supposed to cost. Google is your friend.

Impressive that you were right–and sure enough of it to stick with your estimate. At a newsletter meeting where someone was tossing around numbers (this involved money, so it didn’t seem unreasonable that we’d want to get our estimates right), I was fairly sure none of them added up, but I couldn’t narrow down my reasons well enough to challenge her.

As to your Twitter question, your prose is great.

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Thanks. Actually math didn’t keep me out of college, it kept me from graduating. I learned that in two semesters. As far as prose, I probably would have majored in literature. I fret over composition even in the shortest blog posts.

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Oops. Sorry–I was relying on memory. Or I was reading too quickly to begin with.

Only one math class was required when I started college, and I sweated blood for a C. (How I got even that I can’t explain.) Then I quit for 12 years, and when I went back they weren’t requiring math at all. I was furious. All that agony and I could’ve skipped it?

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I usually make the joke “math kept me out of college” when complicated problems come up because most folks don’t follow up on that. If I say “math kept me from graduating”, then inevitably someone will reply “there’s developmental classes for that”. Indeed. It was the developmental class I failed – twice.

On a side note, I passed geometry (in high school) easily. It made sense to me because it was not abstract.

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Just posted a link: http://notesfromtheuk.com/2015/05/14/follow-up-an-innumerate-triumphs/. Hope you don’t mind me using the word “innumerate.” It popped into my head this morning and it sounds less bacterial than all those words that start with dys-.

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Innumerate is quite appropriate here. It was the basic operations that prevented me from passing even the developmental classes. Thanks for posting that, I got a record-setting number of views.

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