A = 1 + 3 + 32 + 33 +...+ 32011 + 32012
A = ( 1 + 3 + 32 ) + ( 33 + 34 + 35 ) +...+ ( 32010 + 32011 + 32012 )
A = ( 1 + 3 + 32 ) + 33 . ( 1 + 3 + 32 ) +...+ 32010 . ( 1 + 3 + 32 )
A = 13 + 33 . 13 +...+ 32010 . 13
A = 13 + ( 33 +...+ 32010 ) . 13
Vì 13 \(⋮\)13 nên 13 + ( 33 +...+ 32010 ) . 13 \(⋮\)13
hay A \(⋮\)13
~ Hok tốt ~
Chứng minh rằng A=(1+2^2+2^3+......+2^99) chia hết cho 3
Cho B = 1.2.3.....2020.(\(1+\dfrac{1}2+\frac{1}{3}+.......+\frac{1}{2020}\) Chứng minh rằng B chia hết cho 2021.
Bài 1: Cho M = 48+20+a với a là số tự nhiên
Tìm a để M chia hết cho 4, không chia hết cho 4
Bài 2: Tích A =1.2.3.4.5....20 có chia hết cho 400 không
Bài 3:
a, Tìm số tự nhiên n để n+10 chia hết cho n+1
b, Tìm số tự nhiên n để3n +40 chia hết cho n+2
a) Tính nhanh : A = 1- 2 + 3 - 4 +...+ 99 - 100
b) Tìm số nguyên n sao cho : n + 5 chia hết cho n - 2 .
a.Lấy VD 3 câu chia ở thì HTHTTD
b.Chia câu:"She is a teacher" ở thì HTTD,HTHTTD,QKTD,QKHT"
3 người đầu cho 3 tick nha!
IV. Điền giới từ thích hợp cho mỗi câu sau.
1. I live (1) ………………… a small house (2) ………………… the countryside.
2. My house is (3) ………………… a bookstore and a toystore: the bookstore to the left and the toys tore to the right.
3 .Miss Mai wants a kilo ……………… (4) meat and a dozen (5) …………… eggs.
4.Nga goes (6) …………… school (7) ……………foot every morning and she goes (8) ………… home (9) ……… four thirty in the afternoon.
5. Who do you usually play badminton (10) …………………?
HS khối 6 là một số nhỏ nhất khác 0 chia hết cho 9. Khi xếp thành hàng 16,20,32 đều thiếu 3 HS.Tìm số HS khối 6.
Exercise 3 : Chia động từ trong ngoặc ở QKĐ hoặc HTĐ
1. We _________ (go) to the beach last weekend.
2. My cousins _________ (not/ visit) us every weekend.
3. ___________ (your mum/ make) a chocolate yesterday?
4. I _______ (send) Jessica an email yesterday afternoon
5. The children always ______ (do) their homework afternoon.
6. Last year, I ___________ (travel) to Japan.
7. ___________ you ___________ (have) dinner last night?
8. He ___________ (arrive) from the airport at 8:00, ___________ (check) into the hotel at 9:00, and met the others at 10:00.
9. I ___________ (receive) three messages two minutes ago.
10. She ___________ (work) at the movie theater after school.
11. Yesterday she ___________ (go) to the cinema and ___________ (watch) a horror movie.
12. Carlos always ___________ (eat) spaghetti but two days ago he ___________ (eat) soup.
13. We seldom ___________ (drink) alcohol during the forenoon.
14. Somebody ___________ (take) the flowers from the graves in the morning
15. When ___________ your grandpa ___________ (come) home after war?
Exercise 4: Chia các động từ các câu sau ở hiện tại đơn hoặc quá khứ đơn:
1. She……….……….(go) to Australia in 1994 and she liked it verry much.
2. My father usually……….……….(like) his steak well-done.
3. The dog……….……….(eat) its toy last night.
4. The policeman……….……….(talk) to the burglar yesterday.
5. ……….……….(you/have) a test last week?
6. I often see her mother but she never……….……….(speak) to me.
7. The gentleman……….……….(speak) to his servant 2 hours ago.
8. The kangaroo always……….……….(carry) its baby.
9. My friend……….……….(talk) a lot everyday.
10. The man……….……….(drive) to the supermarket last weekend.
11. My brothers……….……….(leave) for England last week.
12. My sisters……….……….(leave) for Endlang every year in June.
13. I don’t like that man because he often ……….……….(laugh) at me.
14. Her sister never……….……….(smoke).
15. The cats usually……….……….(leave) its basket when it is hungry.
16. Mrs.Trang (teach) ……….……….us English last year.
17. Daisy (wear) ……….……….a very beautiful dress last night.
18. Nhung (write) ……….……….to her grandparents very often last year.
19. The teacher usually (give) ……….……….the students a lot of homework on the weekend.
Ex 3: Cho dạng đúng của động từ trong ngoặc
1. Nam often (do) …………………his home work.
2. Minh (watch) ………………..television every night
3. Would you like (play)…………. …badminton?
4. Hoa (not have) ………. a lot of friends in Hue.
5. The students (not go) ……………. to school on Sundays.
6. Nam (go) …………. to the English club every Saturday
7. Nan always (play) ……………basketball in the winter.
8. Ba and Nam (not be)……………….. doctors.
9. He is tired. He’d like (sit) …………….down.
10. His father (not be) ………. ……….a businessman
11. We (live) ………………in a house.
12. Their house (have) ……………..a big yard.
13. Nhung (live)…………………… in the country.
14. Nam’s father (work) …………………in a factory.
15. I (play)…………………….. football in the afternoon.
16. She (eat)……………………… her lunch in the factory.
17. They (go)……………………. to bed at ten?
18. Nam and Ba (watch)……………………. television every Sunday.
19. My sister (listen)………………… to music every day.
20. He (brush) ……………………..his teeth in the morning.
