(n+3).(n+6)=A 
nếu n chia hết cho 2 suy ra (n+6) chia hết cho 2suy ra A chia hết cho 2 (1) 
nếu n không chia hết cho 2 (lẻ) suy ra (n+3) chia hết cho 2 suy ra A chia hết cho 2 (2) 
Từ (1) và (2) suy ra đpcm

 When x is divided by 6 , the remainder is 5 

The remainder when x is devided by 3 is 
 đa: 2

hình như thiếu 1/98
đề đó đúng ko ( 1+ 1/2) x (1+ 1/3) x (1+ 1/4) x...x (1+ 1/98) x (1+ 1/99)

                                   Giải:

( 1+ 1/2) x (1+ 1/3) x (1+ 1/4) x...x (1+ 1/98) x (1+ 1/99)

= 3/2 x 4/3 x 5/4 x … x 99/98 x 100/99

= (3 x 4 x 5 x … x 99 x 100) / 2 x 3 x 4 x … 98 x 99

Giản ước ta được:

= 100/2

= 50

Given K is the midpoint of AB 

If KA = 2x + 1 (cm)

   BK = x + 5 (cm ) then AB = ....11.. (cm )

Bài 2:
1. She started to live in Hanoi 2 years ago.( for)
She has lived in Hanoi for 2 years
2. He began to study English when he was young. ( since)
He studied English since he was young.
3.I have never eaten this kind of food before.
This is the first time I have ever eaten this kind of food.
4.I have never seen such a beautiful girl before. ( she is)
She is the most beautiful girl I have ever met.
5. This is the best novel I have ever read.
I have never read such a good novel before. 

Mấy câu này mình làm mãi

V- BÀI TẬP THÌ HIỆN TẠI HOÀN THÀNH
Bài 1: Cho dạng đúng của động từ trong ngoặc:
1. She arleady ( watch) this movie.

She has arleady watched this movie.

2. He ( write) his report yet?

He has written his report yet?

3. We ( travel) to New York lately.

We have travelled to New York lately.

4. They ( not give) his decision yet.

 They haven't given his decision yet.

5. Tracy ( not see) her friend for 2 years.

Tracy has seen her friend for 2 years.

6. I ( be) to London three times.

I have been to London three times.

7. It ( rain) since I stopped my work.

 It has rained since I stopped my work.

8. This is the second time I ( meet) him.

This is the second time I have met him.

9. They ( walk) for more than 2 hours.

They have walked for more than 2 hours.

10. You ( get) married yet?

Have you got married yet?

bạn có tên tương tương  mình.

Choose one word whose underlined part is pronounced differently : 

1. A.sure       B.saw         C.send    

    D.Sit 

2.A.chopstick                B.touch

    C.catch                        D.stomach

3. A.husk                    B.include

    C.crush                   D.sunbthe

Đặt câu hỏi và câu trả lời

why / famous ?                       _ First woman who won a Nobel Prize

Why was she famous? _ Because she First woman who won a Nobel Prize

how much / children / pay ?  _ Under 18 free (with proof)

How much do the children pay?   _ Under 18 free (with proof)

Look at the picture and match to make sentences.

1  The carnival lorry is     ......B  going to given a balloon by the astronaut.......     2  The lorry has    ......F  been decorated with lost of flowers B  going to given a balloon by the astronaut.

3  The gorilla has   ..... A  been given a banana by the pirate.......   

4  Everyone watching is   ......   D being driven by a clow.

5  The best song might   ....C  be sung by the cowboy..... 

6  Have the costumes    .....E  been bought from a fancy-dress shop?....  

1+2+3+...+n=1275

=> (n+1).n:2=1275

(n+1).n=1275.2

(n+1).n=2550

(n+1).n=51.50

=> n=50