Giải:

Gọi số sách cần tìm là a

Theo đề ra, ta có:

\(a⋮8;12;15\) và \(400< a< 500\)

\(\Leftrightarrow a\in B\left(8;12;15\right)\)

Mà \(BCNN\left(8;12;15\right)=120\)

\(\Leftrightarrow a\in\left\{120;240;360;480;600;...\right\}\)

Vì \(400< a< 500\)

Nên \(a=480\)

Vậy ...

1. She__spends____a lot of money and it going to spend it on a holiday

2. He ___finishes___his homework and he can relax now

3. He___loses___his mobile phone and he doesn't know where it is

4. They___buy___a lot of clothes and don't have any money left

5. He____passes___all his exams and his parents are very pleased with him

6.They___spend_____all their money on computer games

7. She___sends____an email to her friend and is waiting for her friend to write back

1. Where _____do______you (live)_____live_______? I (live)_____live_________in Hai Duong town.

2. What he (do) _________does________now? He (water)________waters_________flowers in the garden.

3. What _______does________she (do)_____do________? She (be)_____is_________a teacher.

4. Where ________are_________you (be) from?

5. At the moment, my sisters (play)_____is playing_______volleyball and my brother (play) _________is playing_______soccer.

6. it is 9.00; my family (watch)__________is watching_________TV.

7. In the summer, I usually (go)_______go_______to the park with my friends, and in the spring, we (have) ______have_______Tet Holiday; I (be)_____am___happy because I always (visit) ______visit________my granparents.

8. ______Does______your father (go)______go_______to work by bus?

9. How _____does______your sister (go)______go_____to school?

10. What time _______do______they (get up)_________get up________?

11. What ____do________they (do)________do________in the winter?

12. Today, we (have)______have________English class.

13. Her favourite subject (be)_________is_________English.

14. Now, my brother (like)______likes___________eating bananas.

15. Look! A man (call)_______is calling__________you.

16. Keep silent ! I (listen )_________am listening___________to the radio.

17. _______Are_______ you (play)_______playing__________badminton now?

18. Everyday, my father (get up)________gets up_______at 5.00 a.m.

19. Every morning, I (watch)______watch___________tv at 10.00.

20. Everyday, I (go) _____go_____to school by bike.

Giải:

Gọi cố học sinh của trường học là a.

Theo đề ra, ta có:

\(a⋮3;4;7;9\) và \(1600< a< 2000\)

\(\Leftrightarrow a\in B\left(3;4;7;9\right)\)

Mà \(BCNN\left(3;4;7;9\right)=252\)

\(\Leftrightarrow a\in\left\{252;504;...;1764;2016;...\right\}\)

Vì \(1600< a< 2000\)

Nên \(a=1764\)

Vậy ...

Số các số có 4 chữ số tận cùng là 8 là:

(9998-1008):10+1=900 (số)

Tự tóm tắt

Giải:

1N ứng với số kg ở xích đạo là:

\(\Delta P=\dfrac{m_1}{P_1}=\dfrac{1}{9,78}\left(kg\right)\)

12,225N ứng với số kg ở xích đạo là:

\(m_2=\Delta P.P_2=\dfrac{1}{9,78}.12,225=1,25\left(kg\right)\)

Vậy ...

vì néu n lẻ thì n+1 chẵn mà lẻ nhân chẵn bằng chẵn chia hết cho 2 mà nếu n chẵn thì n+1 lẻ mà chẵn nhân lẻ bằng lẻ nên n(n+1) chia hết cho 2