3/7 × 5/4 - 5/4 × 5/14

= 5/4 × (3/7 - 5/14)

= 5/4 × 1/14

= 5/56

bạn kia sai

Bài 8:

Chu vi hình vuông là \(\dfrac{5}{7}\times4=\dfrac{20}{7}\left(m\right)\)

Diện tích hình vuông là \(\dfrac{5}{7}\times\dfrac{5}{7}=\dfrac{25}{49}\left(m^2\right)\)

Bài 9:

Số mét vải cần dùng để may 3 chiếc túi là:

\(\dfrac{2}{3}\times3=2\left(m\right)\)

Bài 10:

a: \(\dfrac{1}{2}\times\dfrac{1}{4}\times\dfrac{1}{6}=\dfrac{1\times1\times1}{2\times4\times6}=\dfrac{1}{48}\)

b: \(\dfrac{5}{2}\times\dfrac{1}{3}+\dfrac{1}{4}=\dfrac{5}{6}+\dfrac{1}{4}=\dfrac{10}{12}+\dfrac{3}{12}=\dfrac{13}{12}\)

c: \(\dfrac{5}{2}+\dfrac{1}{3}\times\dfrac{1}{4}=\dfrac{5}{2}+\dfrac{1}{12}=\dfrac{30}{12}+\dfrac{1}{12}=\dfrac{31}{12}\)

1. Despite being tired, I stayed up late to complete my homework. (rewritten with "despite")
2. Camping is less comfortable than staying in a hotel. (rewritten with "than")
3. My son used to read comic books every night when he was nine. (rewritten with "used to")
4. You are not allowed to take photos in the museum. (rewritten with "You")
5.  

1 Despite being tired, I stayed up late to complete my work

2 Staying in a hotel is more comfortable than camping

3 My son used to read comics books every night when he was nine

4 You mustn't take photos in the museum

1. A local festival is different from an international festival in its scale. (Local festivals are typically smaller and more community-oriented than international festivals.)
2. The next semester will start on the 5th of January. (This sentence clarifies the start date of the semester.)
3. Although the bus was late yesterday, I still arrived at school on time. (This sentence uses "although" to show contrast between the lateness of the bus and your timely arrival.)

1 Local festival is different from international festival in its scale

2 The next semester starts on 5 th January

3 Although the bus was late, I still arrived at school on time yesterday

ôí rôì ôi @-@

1. Schools typically have breaks during the Tet holiday and the summer. (This order makes the most sense for a school schedule)
2. People will use self-driving cars to travel around cities more easily. (This clarifies the purpose of self-driving cars)
3. You must show your passport at the security check at the airport. (This follows the logical order of airport procedures)
4.  

Bác HỒ hả

bać naò ??

số tiêǹ quả trưnǵ gà là:2.500

                           viṭ là:3.000

environment: Môi trường nhé bạn

Là môi trường nhé.

Gọi số cần lập là \(\overline{abcd}\)

a có 4 cách chọn (khác 0), b có 4 cách chọn (khác a), c có 3 cách chọn (khác a,b), d có 2 cách chọn

\(\Rightarrow\) Có \(4.4.3.2=96\) số

Trong 210 ml dung dịch cồn 90 độ có số etanol là:

\(\dfrac{210.90}{100}=189\left(ml\right)\)

Gọi số nước cần thêm vào là x (ml), ta có:

\(\dfrac{189}{x+210}=\dfrac{70}{100}\)

\(\Rightarrow x+210=\dfrac{189.100}{70}=270\)

\(\Rightarrow x=60\) (ml)