To compare decimals such as 0.04 and 0.4, first, line up the decimal points of the two numbers.
Next, we compare the digits place by place starting on the left.
Notice that 0 and 0 are the same but moving to the right one column, notice that 0 is less than 4 so 0.04 is less than 0.4 or stated another way, 0.4 is greater than the decimal 0.04.
A common mistake is to see the 4 is 0.04 and 0.4 and assume that these decimals are equivalent but don't fall into this trap.