Or... you can use the LCM (least common multiple) for your new denominator: The LCM of 4 and 10 is 20... Let's make the changes... So again! How about this one? Which is greater: or ? Let's use as our new denominator (it's the LCM): So Head on over to the next page to try some fraction practice problems... Previous continue 1 2 3 of 3