Answer :

Its not . If you múltiple 3/4 to have a common den. That it would be multiplied by 3 would be 5/12 and 9/12 so 3/4 is greater thAn 5/12
Think about it like this. If you have 12 prices you do have more pieces, but there will less to eat. When you have 4, you do have less but there will be more to eat.