What is bigger 1/4 or 0.4 or are they equal

Well, of you change the fraction into a decimal (divide the numerator by the denominator : 1 divided by 4), you get:

(the decimal from 1/4) 0.25 __ 0.4

It's not that hard from there: 0.25 < 0.4

They are equal because if you divide 4:1.0 your answer would be 0.4