Which bigger 40 hundredths or 30 hundredths?

To compare fractions

40/100 or 30/100

Since both have the same denominator of '100' , then just compare the numerators . 30 > 30

Hence it follows that 40/100 > 30/100

To compare decimals.

0.40 and 0.30

#1 ; drop the suffix zeroes , they are trivial

Hence 0.4 & 0.3

#2 ; drop the decimal points

Hence 04 & 03

#3 ; drop the prefix zeroes

Hence

4 & 3

I think you will agree with me that 4 > 3 . Hence it follows that 0.40 > 0.30

NB This method is good for comparing any decimals.