4m2 5cm2=40005cm2

36. Lan’s mother said, “My daughter usually brushes her teeth before meals.”
=> Lan's mother said that her daughter usually brushed her teeth before meals

37. They said, “We have to do the assignments now.”
=> They said that they had to do the assignments then.

38. Lan says, “My sister seldom rides a bike to school.”
=> Lan said that her sister seldom rode a bike to school.

39. They said, “Our teacher sometimes explains the difficult lesson.”
=> They said their teacher sometimes explained the difficult lesson.

40. Nam said, “I am doing my homework now.”
=> Nam said he was doing his homework then.

a,

2010dm3= .....2,010 m3....

3m3 5dm3= ...3,005

b, 

4m2 7dm2 =....4,07...

9dm2 5cm2 = .0,0905.......

A .Bảo vệ môi trường sống

Phương thức biểu đạt của văn bản tục ngữ về con người và xã hội là biểu cảm

$\frac{12}{14}$=$\frac{6}{7}$

ta rút gọn cả tử số và mẫu số cho 2