Una has a collection of insects: 1/4 are butterflies, 2/7 are moths, and the rest are beetles.
HOW MANY INSECTS ARE BEETLES?
you have to tell us how many insects there are in all
1 -1/4 - 2/7 = betles
1-7/28- 8/28 = beetles
28/28 - 7/28 - 8/28 = 13/28 are beetles
13/28+7/28+8/28 = 1
You can't attach a number on the beetles, but just a fraction of Una's overall collection. That fraction comes to: 13/28 of her collection are beetles.
+63 
+37153 
