① There are 600 chickens and ducks. How many chickens and ducks are there in the farm? Duck: 600÷( 1+ 1/3)=450 (only) chicken: 450× 1/3= 150 (only)

② There are more than 300 chickens in Abby Mallard. How many ducks are there? Duck: 300( 1- 1/3)= 450 (only)

③ There are 200 fewer chickens than ducks. How many chickens are there? 200÷ (1-1/3) ×1/3 =100 (only).

Second,

There are 60 peach trees in the orchard.

The number of pear trees planted is three quarters of that of peach trees. How many pear trees are there? Peach is "1" pear: 60×3/4=45 (tree)

There are a quarter more pear trees than peach trees. How many pear trees are there? Peach is "1" pear: 60×( 1+ 1/4)=75 (tree).

③ The number of pear trees planted is one third less than that of peach trees, and the number of peaches in pear trees is "1":60× (1-1/3) = 40 (plants).

(4) is three-quarters of the pear tree. How many pear trees are there? Pear is "1"60 ÷ 3/4 = 80 (tree).

⑤ It is one third less than that of pear trees, and the number of pears in pear trees is "1"60 ÷ (1-kloc-0//3) = 90 (plants).

Third,

Xiaoli read a novel. On the first day, she read a fifth of the book, and the next day, she read a quarter of the book.

The next day I read twenty more pages than the first day. How many pages does this novel have?

The whole book is "1"20 ÷ (1/4-1/5) = 400 (pages).

There are 220 pages left How many pages does this novel have?

The whole book is "1"220÷ (1-1/4-1/5) = 400 (pages).