When a single digit trails the decimal point the number represents tenths. So 3.6 as a mixed number would be 3 6/10, which reduces to 3 3/5.
As a fraction (an "improper" fraction) multiply the denominator by the whole number and add the numerator. Write the result back over the denominator. Note: The denominator does not change.
So 3x5 = 15, plus 3 (in the numerator) = 18. 3 3/5 = 18/5 as an improper fraction. As the denominator shares no factors with the numerator, this fraction cannot be further simplified.
