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Post Info TOPIC: i have a question about bases...
Anonymous

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i have a question about bases...
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how would you convert 32.42 base 5 to base 10? i can figure it out with just the decimal part but i dont know what to do know that there's a whole number. do i do it seperately or together? also another one similar is 11 1/2 to base 4.

help is appreciated. 79

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separate whole and decimal, convert to base 10, add back together

32.42 base 5
32 ---> 17
.42 ---> 22/25 --> .88

17.88

11.2 base 4   (.2 not .5 i think)
11 ---> 5
.2 ---> 1/2
5 1/2
fraction stays the same when going to bigger bases, but it might change when going to smaller bases - not sure about that though

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fht


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Another interesting thing which might be easily brought out concerning bases and fraction are repeated fractions in a different base.
For example, change .33333... in base 5 to base 10.
The shortcut lies in converting the repeated fraction into the sum of an infinite converging geometric series. Videlicet, .3333.... in base 5 is 3/5+3/25+3/125+3/625+..., then just use the formula for the infinited series. Ergo .33.. base 5 = 3/5 / 4/5 = 3/4.
Best Wishes

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Best Wishes


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yeah... .aaa...  in base b =  a/(b-1)

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Anonymous

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okay thanky you. it makes more sense now. :)

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Anonymous

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I think decimals are the NEGATIVE powers of the base number. For example 10.42 in base 10 is (1*10^1) + (0*10^0) + (4*10^-1) + (2*10^-2).

Making any sense? Sorry if it's still foggy.

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