What is 0.4 as a simplified fraction

2/5

Step-by-step explanation: 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 4/10.

Notice however that 4/10 is not in lowest terms so we need to divide the numerator and the denominator by the greatest common factor of 4 and 10 which is 2.

So if we divide the numerator and the denominator by 2, we get the equivalent fraction 2/5.

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