We're lost. Pass me the compass

It's so hot today. I need to take some sun cream

My head hurt. I need to take a painkiller

I finished packing. All my things are in my backpack

I walked too much. I need to put a plaster on my foot.

a) Phân tích số 111 ra thừa số nguyên tố rồi tìm tập hợp các ước của 11

111 = 3 . 37

=> Ư (111) = {1; 3; 37; 11}

b) Thay dấu * bởi chữ số thích hợp:

** . * = 111

Từ câu a => 37 . 3 = 111

Tính chất giao hoán của phép cộng:

a + b = b + a

Tính chất giao hoán của phép nhân:

a . b = b . a

Tính chất kết hợp của phép cộng:

(a + b) + c = a + (b + c)

TÍnh chất kết hợp của phép nhân:

(a . b) . c = a . (b . c)

Tính chất phân phối của phép nhân đối với phép cộng:

a(b + c) = ab + ac

111 : a dư 15 \(\Rightarrow111-15⋮a\Rightarrow96⋮a\) với a > 15

180 : a dư 20 \(\Rightarrow180-20⋮a\Rightarrow160⋮a\) với a > 20

\(\Rightarrow a\inƯC\left(96,60\right)\)với a > 20

Ta có:

96 = 2⁵ . 3

60 = 2² . 3 . 5

=> ƯCLN (96, 60) = 2² . 3 = 12

=> ƯC (96, 60) = {1; 2; 3; 4; 6; 12}

=> a \(\in\) {1; 2; 3; 4; 6; 12}

Mà a > 20 => Không tìm được a

Số lớn nhất là số lẻ có ba chữ số chia hết cho 5 là 995.

Số bé nhất là số lẻ có ba chữ số chia hết cho 5 là 105.

Có tất cả:

(995 - 105) : 10 + 1 = 90 (số )

Đáp số: 90 số.

Hello, my name is Nam. I'm twelve and I'm a student. I have a sister, Nga. She is an engineer. She's twenty-five. Whe live in a house in the country. Our house has a beautiful yard. There are flowers and plants in the yard.

1. How old is Nam?

=> Nam is twelve years old.

2. Does he have a brother?

=> No, he doesn't. He has a sister.

3. What is his sister's name?

=> Her name is Nga.

4. What does she do?

=> She is an engineer.

5. Where do they live?

=> They live in a house in the country.

6. Does Nam's house have a yard?

=> Yes, it does.

7. What are there in the yard?

=> There are flowers and plants in the yard.

2. your father's armchair / big

=> Which is your father's armchair? It is the big armchair.

3. her erasers / small

=> Which are her erasers? They are the small erasers.

4. his store / big

=> Which is his store? It is the big store.

5. Mai's books / old

=> Which are Mai's books? They are the old books.

6. your schoolbag / new

=> Which is your schoolbag? It is the new schoolbag.

5 My house is on Nguyen Hue Street.

2 My name is Nga. How old are you?

1 Hello, I'm Mai. What's your name?

4 I'm eleven. Where's your house, Mai?

9 It 's the small one. Its name is ''Cheer''.

7 A bookstore.

6 What's next to your house?

8 There are two bookstores on Nguyen Hue Street. Which bookstore is it?