3.3.2 In the form: .ababa …

In a similar vein, fractions in the form .ababab.ababab \dots can be treated as:

.ababab=ab100+ab10000+ab1000000+=ab10011100=ab100×10099=ab99.ababab \dots = \frac{ab}{100} + \frac{ab}{10000} + \frac{ab}{1000000} + \dots = \frac{\frac{ab}{100}}{1 - \frac{1}{100}} = \frac{ab}{100} \times \frac{100}{99} = \frac{ab}{99}

Where abab represents the digits (not a×ba \times b). Here is an example:

.242424=2499=833.242424 \dots = \frac{24}{99} = \frac{8}{33}

You can extend the concept for any sort of continuously repeating fractions. For example, .abcabcabc=abc999.abcabcabc \dots = \frac{abc}{999}, and so on.

Here are some practice problems to help you out:

Problem Set 3.3.2

.272727dots=.272727 \\dots =
.414141dots=.414141 \\dots =
.212121dots=.212121 \\dots =
.818181dots=.818181 \\dots =
.363636dots=.363636 \\dots =
.020202dots=.020202 \\dots =
.727272dots=.727272 \\dots =
.151515dots=.151515 \\dots =
.308308dots=.308308 \\dots =
.231231dots=.231231 \\dots =
.303303dots=.303303 \\dots =
.099099099dots=.099099099 \\dots =