Question

Write 3.6 as a fraction or a mixed number

Answer 1

As a fraction is would be 18/5
As a mixed number it would be 3 3/5

Answer 2

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.