What is 0.4 as a fraction?

To convert the decimal 0.4 into a fraction, you can start by recognizing that the decimal is equivalent to "4 tenths." This is because 0.4 is in the tenths place. Thus, it can be expressed as the fraction 4/10.

Next, to simplify 4/10, both the numerator and denominator can be divided by their greatest common divisor, which is 2. When you divide both by 2, you arrive at 2/5.

The fraction 2/5 accurately represents the decimal equivalent of 0.4 because when you divide 2 by 5, you get 0.4 as the decimal result. This process ensures that 0.4 is correctly interpreted as a fraction in its simplest form.

Therefore, 2/5 is the right answer.