Anytime you have a fraction or a slash, you can divide to get the answer, which in this case is a decimal.
13 ÷ 22 is: 0.59090909
Now, when you have a repeating number of set of numbers (09) you draw a straight, horizontal line over the repeating number or numbers to show that they repeat, so you do not have to keep writing it.
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So, the final answer is: 0.5909
Note: In case you are wondering why the line doesn't go over the 90 ... that is because the zero at the end would indicate the end of the number and get dropped, which would not be exactly correct.