how do you convert a decimal into a fraction?

Multiply by enough 10's to turn the decimal into an integer and then divide by that many 10's, then simplify if necessary.

For example to turn 0.514 into a fraction multiply by 1000 to get 514 then divide by 1000 to get 514/1000 =2*257/(2*500) = 257/500.

 

If it's a repeating decimal you need to do it differently.  Look at 0.3333...... for example:

Let f = 0.333333..... 

10f = 3.33333......

Subtract f from 10f to get 9f = 3  

Divide both sides by 9 to get f = 3/9

Simplify: f = 1/3

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