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I'm glad you pointed this out to your teacher. It is worth noting, though, that if it weren't for the arbitrary "If it's exactly halfway inbetween, you should j
by Chinjut 12y ago
I'm glad you pointed this out to your teacher. It is worth noting, though, that if it weren't for the arbitrary "If it's exactly halfway inbetween, you should just round it up" rule taught as received wisdom in school, your teacher would've been on stronger ground. And it is reasonable that they were attempting, in their way, to convey (or even fully come to terms with themself) the understanding that the nearest integers to a value are always also among the nearest integers to the nearest multiples of 0.1 to that value (and all the generalizations of this); it's just that sometimes there are other nearest integers to nearest multiples of 0.1 as well.
- danielweber 12y agoThe "0.5 rounds up" is kind of arbitrary, but it has the advantage of "you only need to look one digit out to round." 4.49 obviously rounds to 4. 4.51 obviously rounds to 5. 4.50, since it "should"[1] follow the same rules as any other number that starts with "4.5", thus rounds to 5. Say I were looking at a real number of arbitrary length, such that it starts with 4.500000000000... and maybe has a non-zero digit somewhere in it before it terminates. With the "round up on .5" rule, I don't have to keep on reading out indefinitely to round it. [1] This "should" is assertion.