Write 0.4 as a fraction.

Using the place value chart we can see that the decimal 0.4 is four tenths, so we can write 0.4 as the fraction 4 out of 10 or [tex]\frac{4}{10}[/tex]. Notice however that [tex]\frac{4}{10}[/tex] is not in lowest terms so we need to divide both the numerator and denominator by the greatest common factor of 4 and 10 which is 5.

Therefore, 0.4 can be written as the fraction 2/5, which is in lowest terms.