Explanation:
come on now :
how many wholes are in a whole ? 1
how many halves are in a whole ? 2
how many thirds are in a whole ? 3
how many fourths are in a whole ? 4
how many fifths are in a whole ? 5
how many sixths are in a whole ? 6
and so on and so on.
so, when we see
1 4/5
we see one whole and four fifths.
how many fifths are in that whole ? 5
and we have 4 extra fifths.
that gives us 5 + 4 = 9 fifths
so, Eric has at the beginning
9/5 pounds.
then he uses 3/5 of a pound (three fifths) for the bird feeders on his porch.
that leaves him with
9/5 - 3/5 = 6/5 = 1 1/5 pounds
of birdseed.
FYI : as you can see, we did not even have to bother with the whole.
it was originally
1 4/5, and we removed 3/5 from that. that is less than the extra amount beyond the whole pound.
so, we can simply remove these 3/5 from the extra 4/5 :
4/5 - 3/5 = 1/5
and together with the untouched whole pound we get as remaining amount
1 1/5 pound
it is really that simple.
is there anything you still don't understand ?
please let me know, so that I can help you more with these details.