1. Ta có phép tính:

ab36

-   ab

--------

1917

Để 6 - b = 7 thì b = 9 ,nhớ 1

Để 3 - (a + 1) = 1 thì a = 1

Vậy, số cần tìm là 1936

~ HT :) ~

Bạn tham khảo nhé !

Giải : 

Đổi : 7 giờ kém 15 phút  = 6 giờ 45 phút

Thời gian ô tô đi từ Hà Nội đến Hạ Long là :

10 giờ 45 phút - 6 giờ 45 phút - 15 phút = 3 giờ 45 phút

Đổi 3 giờ 45 phút =  3,75 giờ

Quãng đường từ Hà Nội đến Hạ Long là :

48 x 3,75 = 180 ( km / giờ)

Đáp số : 180 km / giờ.

Giải

7 giờ kém 15 phút = 6 giờ 45 phút

Thời gian ô tô đi từ Hà Nội đến Hạ Long là :

10 giờ 45 phút - 6 giờ 45 phút - 15 phút = 3 giờ 45 phút = 3,75 giờ

Quãng đường từ Hà Nọi đến Hạ Long là :

48 x 3,75 = 180 (km/giờ)

Đáp số : 180 km/giờ.

Hc tốt:3

41. 

Lan received a bike from her parents on her birthday.

42. 

I spend 2 hours each day doing my homework.

43. 

Hoa studies hard.

44. 

Ann is a dangerous driver .

Bạn tham khảo nhé !

1. How long have you been in Africa?

2. I have been there for three years

3. How long has he lived in Berlin?

4. He has lived there since 2002

5. How long has she worn that coat?

6. She has worn it since last winter

7. Where have you been today?

8. I have been at the hospital

9. How long has the detective looked for the man?

10. He looked for him two months

11. Why has she taken my money?

12. She has traveled around the world for four years

13. Where have you put my keys?

14. She has moved to a new house in the country

15. How long has your friend studied German?

16. She has studied German since 1999

17 Have you ever play golf?

18 The documentary has already finished.

19 My teacher hasn`t explained that lesson yet.

20 Kevin has given his mother a nice present.

1.- How long/you/be/ in Africa?

=> How long have you been in Africa ?

2.- I /be/ there/three years.

=> I been there for three years

3.- How long/ he/ live/ in Berlin?

=> Hong long has he lived in Berlin ?

4.- He / live/there/ 2002

=> He has lived there since 2002

5.- How long /she/ wear/ that coat?

=> How long has she worn that coat ?

6.-She/ wear/it/ last winter.

=> She has worn it since last winter ?

7.-Where/ you/be/ today?

=> Where have been today ?

8.- I /be/ at the hospital

=> I have been at the hospital

9.- How long/ the detective/ look/ for the man?

=> How long has thhe detective looked for the man

10.- He/ look/ for him two months.

=> He has looked for him for two months

11.-Why /she/take/my money?

=> Why has she taken my money ?

12.- She / travel/ round the world /for four years

=> She has traveled around the world for four years

13.- Where /you/ put/ my keys?

=> Where have you put my keys ?

14.- She /move/to a new house /in the country

=> She has moved to a new house in the country

15.- How long/your friend/study/ German?

=> How long have your friend stuidied in German ?

16.- She/study/German /1999

=> She has studied in German since 1999

17.- you/play/golf/ ever?

=> Have you played golf ever ?

18.- The documentary /already/ finish

=> The documentary has already finished

19.-My teacher/not/explain/ that lesson/yet

=> My teacher has not explained that lesson yet

20.- Kevin /give/ his mother/ a nice present

=> Kevin has given to his mother a nice present

     giải:

                sợi dây ban đầu dài là:

                     4x(8x2)=64(cm)=0,64m

                                                #HỌC TỐT#

hello moi nguoi, Map ne

Sxq là : \((30+20)x16x2\)=1600(dm²)

ĐS:....

~Hok tốt ~

1000008

Hai lần trung bình cộng ba số là: 

\(15+27-6=36\)

Trung bình cộng của ba số là: 

\(36\div2=18\)

Số thứ ba là: 

\(12-6=12\)