Answer: 2/5
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 out of 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 2/5. So 0.4 can be written as the fraction 2/5 which is in lowest terms.
I have attached the place value in the image attached.
My work is also shown in the image attached