Tuesday, April 9, 2019

numbers - Why are decimals read as fractions by some cultures?

I find it very strange that the top results on Google for "how to read decimal" give me a very strange way to read them - as fractions.




I have learnt to read the digits individually and it makes a lot of sense. There is no fumbling with which "-ths" the fractional part is, and there's no confusion for the listener. The ESE QA here and here also agree with me.



However, I find that the system of reading decimals as fractions is being widely taught and accepted.



The top result here has an example: What is the numerical value of "two hundred thousandths"? Three students gave the answers as follows:




  • Student 1: 200,000.

  • Student 2: 0.200

  • Student 3: 0.00002




Apparently only Student 2 is right. The explanation given is that the individual answers when converted to words would be:




  • Student 1: two hundred thousand

  • Student 2: two hundred thousandths

  • Student 3: two hundred-thousandths




And that Student 3 is wrong because the question did not contain a hyphen.



But here's what I don't understand: How do you state the hyphen when actually speaking the number out loud? Do you say "two hundred hyphen thousandths", or do you simply say "t-w-o hundredthousandths" (saying the second word as compressed as possible)?



According to other sources like this video, even the question is wrong, as the "correct" answer by Student 2 should actually be read as "two tenths", ignoring the insignificant zeros.



I am trying to understand how this system came to be and why it is accepted over the simpler system of reading out the digits individually after the decimal point:




  • Student 1: two hundred thousand.


  • Student 2: zero point two.

  • Student 3: zero point zero zero zero zero two.

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