Navigating through number and operations in grades National Council of Teachers of Mathematics.
Contexts of use[ edit ] The thou, or mil, is most commonly used in engineering and manufacturing. For example in specifying: The thickness of items such as paper, film, foil, wires, paint coatings, latex gloves, plastic sheeting, and fibers For example, most plastic ID cards are about 30 thou 30 mils in US 0.
Card stock thickness in the US is usually measured in points or mils that gives the thickness of the sheet in thousandths of an inch. In the manufacture of automobile engines A typical example is the thickness of the head gasket, or the amount of material to be removed from the head to adjust the compression ratio of the cylinders.
In the servicing of automobile engines Typical examples include a spark-plug gap or ignition points gap. The manufacture of printed circuit boards PCBs  although the component dimensions are now typically provided in millimetresbecause they are sold worldwide Tolerance specifications on hydraulic cylinders There are also compound units such as "mils per year" used to express corrosion rates.
Tenths[ edit ] In machiningwhere the thou is often treated as a basic unit, 0.
Machining "to within a few tenths" is often considered very accurate, and at or near the extreme limit of tolerance capability in most contexts. Greater accuracy tolerance ranges inside one tenth apply in only a few contexts: Usage notes on mil versus thou[ edit ] In the United States, mil was once the more common term,   but as use of the metric system has become more common, thou has replaced mil among most technical users to avoid confusion with millimetres.
Equivalence to other units of length[ edit ] 1 thou is exactly equal to: Each of these "equivalents" is off by an amount that is negligible for most practical purposes—for example, 2 tenths on a plus-minusthou tolerance.
But the point here is horse sense on the fly—quick common-sense mental math to keep oneself oriented when machining and inspecting.
History of usage[ edit ] The introduction of the thousandth of an inch as a sensible base unit in engineering and machining is generally attributed to Joseph Whitworth  who wrote in Each 64th is about 16 thou.
Communication about sizes smaller than a 64th of an inch was subjective and hampered by a degree of ineffability —while phrases such as "scant 64th" or "heavy 64th" were used, their communicative ability was limited by subjectivity.
Dimensions and geometry could be controlled to high accuracy, but this was done by comparative methods: Such work could only be done in craft fashion: Although measurement was certainly a part of the daily routine, the highest-precision aspects of the work were achieved by feel or by gauge, not by measuring as in determining counts of units.
This in turn limited the kinds of process designs that could work, because they limited the degree of separation of concerns that could occur.
The introduction of thou as a base unit for machining work required the dissemination of vernier calipers and screw micrometers throughout the trade, as the unit is too small to be measured with practical repeatability using rules alone.
Most rule markings were far too wide to mark a single mil, and even if such dividing is accomplished, it is illegible to the naked eye, being discernible but not useful for measuring.
During the following half century, such measuring instruments went from expensive rarities to widespread, everyday use among machinists. Bringing more metrology into machining increased the separation of concerns to make possible, for example, designing an assembly to the point of an engineering drawingthen having the mating parts made at different firms who did not have any contact with or even awareness of each other—yet still knowing with certainty that their products would have the desired fit.Ten tenths makes one whole.
We can write that as a multiplication: 10 × = 1. (Note: the word “makes” corresponds to the equal sign, but there is no word to correspond to the multiplication sign; it is implied.) Fill in the sentences below, and write a multiplication sentence to match each one.
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The thousandth place is three places to the right of the decimal regardbouddhiste.com://regardbouddhiste.com Write a zero Write a decimal point Write a zero Write a zero Write a zero Write any digit less than 5 (if you wrote a zero you will have to write another digit or as many zeros as you want, and then a regardbouddhiste.com How do you write thirty five thousandths in decimal form How would you write a decimal that is less than five Ten thousandths How would you write a decimal that is less than 5 ten thousandths?
Write six and four hundred eight thousandths as a decimal What is the equivalent decimal for thousandthsregardbouddhiste.com