How do you turn a 3.9 into a fraction?

Answer 1

(1) Write the number without any decimal points.

(2) Divide it by a power of ten. The power of ten that you use is the same as the number of digits after the decimal point in the original number.

(3) Simplify the fraction by eliminating common factors (if any). Also, convert from vulgar to mixed fraction if required or desired.

So here 3.9 = 39/10 and no further simplification is possible. In mixed fraction form this would be 3 9/10