Mark the location of No.1 Middle School and Bookstore on the map according to the following description. ① No.1 Middle School is 600 meters in the northeast. ② The bookstore is due south of No.1 Middle School. (1)600÷ 100=6 (cm),

Because No.1 Middle School is 30 degrees northeast,

So the position of No.1 Middle School is shown in the following figure;

(2)300÷ 100=3 (cm),

Because the bookstore is just south of No.1 Middle School,

So the location of the bookstore is as shown in the figure below:

(3) According to the picture, the bookstore is in a small southeast direction.

So the answer is: due east by south.