khi lấy số bị chia trừ với số đó, lấy số chia cộng với số đó thì tổng của chúng không đổi và bằng:

12+6=18

số mới là:

18/2=9

vậy số cần tìm là :

12-9=3 hoặc 9-6=3

21.d

22.a

23.b

25.d

26.c

27.a

28.b

29.d

30.b

1. No one in my class is talker than Peter.

-> Peter . . . .is the tallest student in my class. . . . . . . . . . . . . . .

2. According to me, English is easier than Maths.

-> According to me, Maths . .is more difficult than English . . . . . . . . . .

3. No one in my group is more intelligent than Mary.

-> Mary . . . .is the most intelligent in my group . . . . . . . . . . . . . . .

4.No river in the world is longer than the Nile.

-> The Nile . . . is the longest river in the world. . . . . . . . . . . .

5. Mount Everest is the highest mountain in the world.

-> No mountain . . in the world is higher than Mount Everest. . . . . . . . . . . . . . . . . . . .

6. This is the first time I have ever met such a pretty girl.

-> She is . . . . .the first preety girl I have met. . . . . . . . . . . . . . . . . . .

7. He works much. He feels tired.

-> The more . . . . . he work, the more he tired.. . . . . . . . .

8. This computer works better than that one.

-> That computer . . .works worse than this one . . . . . . . . . . . . . . . . . .