# back-of-the-envelope calculation

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## back-of-the-envelope calculation

A calculation or mathematical formulation that is approximated in a quick, informal, and rough manner, as might be sketched out on a scrap of paper (such as the back of an envelope). When it came time to pay the bill, we had to do some back-of-the-envelope calculations to figure out who owed how much.
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Some regulators do engage in a back-of-the-envelope calculation by multiplying an average hourly wage rate and regulatory compliance hours, but many do not, in part because arriving at an acceptable value for an hourly wage rate is no small feat.
A back-of-the-envelope calculation reveals that these numbers rival diesel efficiency and if mogas is factored into the equation, flying a 912 iS-equipped aircraft is substantially less expensive than the equivalent 912 ULS.
My own back-of-the-envelope calculation suggests a yield of between 4 and 15 kilotons.
A back-of-the-envelope calculation, assuming a \$100 million figure, suggests that this would lead to only a \$100 credit to the poorest one-third, which comes out to be about \$8 per month.
The decision will help a third of its home loan customers of more than 17 lakh in bringing down interest payments by as much as two percentage points, or a gain of about Rs 6,000 a month on a 20-year, Rs 50-lakh mortgage, a back-of-the-envelope calculation shows.
One source, who is not involved in the project but did a back-of-the-envelope calculation, estimated it would take blended rents of about \$110 per foot for the project to break even.
If one calculates these percentage increases as national income projections over an 80-year period (providing for a 20-year delay before any school reform is completed and the newly proficient students begin their working careers), a back-of-the-envelope calculation suggests gains of nothing less than \$75 trillion over the period.
The climate impact of this economic strategy is less often considered, and yet if we assume that each student returns home only once in each academic year, then a back-of-the-envelope calculation indicates that this produces more in terms of CO2 emissions than they are entitled to under the sorts of global limits that would ensure climate stability.
A back-of-the-envelope calculation suggests Labour would lose 13 of their 29 seats in Wales, leaving them with fewer than half.
That means, by a back-of-the-envelope calculation, there is one cancer cell for every 100 quadrillion normal bone marrow cells nationwide per year, he said.
That amounts to 120 issues, several hundred articles, and, by a back-of-the-envelope calculation, over 3 million words--and counting.
A back-of-the-envelope calculation suggests that if China could allocate capital more efficiently, it would reduce its investment intensity from the current 40 percent of GDP to 35 percent without sacrificing its economic growth (and hence deliver a greater improvement to its citizens' living standard).
Simple back-of-the-envelope calculation indicates that an AIS receiver fitted on a low-Earth-orbit satellite can provide tactical-level information on a near-real-time basis.
By my back-of-the-envelope calculation, that means General Sherman produces about 75 sextillion molecules of oxygen annually.
A back-of-the-envelope calculation, assuming that one could study a patent in as little as 10 minutes, and do this nine hours a day, six days a week, shows that the inventor would have been at it for 12 years if he did nothing else.
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