(2) A teaching building with an area of about 300 square meters.
(3) Xiao Di's thumb nail area is about 65438±0 cm2.
A pencil is about 20 centimeters long.
(5) A square with a side length of 1 cm and an area of1cm 2; A square with side length 1 m and area 1 m2; The area of handkerchief is about 4 square decimeters; The area of the classroom is about 60 square meters.
(6) Xiao Liang's waist is 5 decimeters.
The building area of a house is about 45 square meters.
The area of a bookmark is about 8 square centimeters.
The area of a CD is about 1 square decimeter.
The length of this classroom is 8 meters.
(1 1) The area of the exercise book is about 2 square decimeters.
So the answer is: square decimeter, square meter, square centimeter, centimeter, square centimeter, square meter, square meter, square meter, square centimeter, square decimeter, meter, square decimeter.