Can we write bar35 or (353535.....) In form of p/q where q is not equal to 0 ? Thanks

1 Answer
Apr 22, 2018

0.¯¯¯¯35=3599

Explanation:

In Socratic we can write 0.overline{35} between hashtag signs and it renders as

0.¯¯¯¯35

That's pretty nice. I found it by trying some LaTeX, whose features have been partially adapted.

Turning to the problem, whenever we have a purely repeating decimal like this, where the repeating part starts right after the decimal point, we quickly get the fraction by just adding a denominator of nines whose length is the length of the repeating part.

0.¯¯¯¯35=3599

That's nice for quickly getting the answer, but why does it work? It works because a purely repeating decimal is really a geometric series in disguise, and the same trick for adding up a geometric series works for a repeating decimal:

x=0.¯¯¯¯35

100x=35.¯¯¯¯35

100xx=35

x=3599