1, 500/ 1200=5/ 12 for completing the whole month's tasks in the first half of the year.

Mid-term completion is 500/( 1200-500)=5/7.

2、

The greatest common factor of 48 and 84 is 12.

You can be assigned to 12 classes at most, with 4 schoolbags and 7 books in each class.

3、

5/ 12= 15/36

7/ 18= 14/36

13/36

Fruit trees have the largest area and willow trees have the smallest area.