Do tổng = số lớn + số bé nên 2010 = tổng x 2

⇒ Tổng của 2 số là: 2010 : 2 = 1005

Số bé là: (1005 - 192) : 2 = 406,5

Số lớn là: 1005 - 406,5 = 598,5

Đáp số: 406,5 và 598,5

S = 3 + 3² + 3³ + ... + 3²⁹ + 3³⁰

3S = 3² + 3³ + 3⁴ + ... + 3³⁰ + 3³¹

2S = 3³¹ - 3

S = \(\dfrac{3^{31}-3}{2}\)

Xét 3³¹ có tận cùng = 7

Ta có: 7 - 3 = 4

⇒ S có tận cùng = 2 hoặc 7

is/has

I like living in the countryside!¹ The air here is way more fresh than in the city. I'm also really into the peaceful sceneries and lifestyles here, although the city brings more modern vibes.² The countryside is a place that I would choose to rest and get to know people.³ The people here is actually really friendly and hard-working too.⁴ I could immerse myself in different places instead of looking at the screens like I used to.⁵ Maybe I could also learn a lot of new skills here and I would be able to have a very chill life like I have always wanted.⁶ The city is a place that seems to be more rich and complicated but compare to the geniune, lovely countryside, It's just a different story.⁷

(-):

1. There aren't four chairs in the living room.

2. I don't get up at 6 every morning.

3. Mrs. Hoa doesn't go to the supermarket on Sundays.

4. My father doesn't often drink tea every morning.

5. He doesn't usally read books in the library.

(?):

1. Are there four chairs in the living room?

2. Do you get up at 6 every morning?

3. Does Mrs. Hoa go to the supermarket on Sundays?

4. Does your father drink tea every morning?

5. Does he usually read books in the library?

\(\dfrac{3\times7}{5\times7}=\dfrac{21}{35}\) ; \(\dfrac{4\times5}{7\times5}=\dfrac{20}{35}\)

\(\dfrac{20}{18}=\dfrac{10}{9}\) ; \(\dfrac{10\times5}{9\times5}=\dfrac{50}{45}\) ; \(\dfrac{2\times9}{5\times9}=\dfrac{18}{45}\)

\(\dfrac{5\times4}{6\times4}=\dfrac{20}{24}\) ; \(\dfrac{3\times6}{4\times6}=\dfrac{18}{24}\)

1. will call

2. will be

3. will watch

4. travel

5. is practicing

6. will study

Số thứ 2 hơn số thứ nhất là: 105 + 240 = 345

Hiệu số phần bằng nhau là: 7 - 2 = 5 (phần)

Số thứ nhất là: 345 : 5 x 2 = 138

Số thứ 2 là: 345 - 138 = 207

Đáp số: 138 và 207

@Đỗ Ngọc Thanh Vân: Thế kết quả đâu mà tìm đây ta.

Biểu thức trên = \(x\times37+\left(1-2\right)+\left(3-4\right)+...+\left(35-36\right)+37\)

\(=x\times37+\left(-1\right)\times18+37\)

\(=x\times37-18+37\)

\(=x\times37+19\)