Diện tích trồng ngô là:

\(80\cdot80\cdot\dfrac{3}{4}\cdot\left(100\%-32.5\%\right)=3240\left(m^2\right)\)

ảnh bị lỗi kìa bạn

a: Xét tứ giác BHCD có 

BH//CD

CH//BD

Do đó: BHCD là hình bình hành

Hộp bánh còn lại nặng số kg là: 

`4/5 - 1/4 = 11/20 (kg)`

ko nhìn rõ bạn ơi

Bài \(5\) : Tính

\(\dfrac{8}{15}-\dfrac{2}{5}=\dfrac{8}{15}-\dfrac{6}{15}=\dfrac{2}{15}\)

\(\dfrac{1}{3}-\dfrac{1}{4}=\dfrac{4}{12}-\dfrac{3}{12}=\dfrac{1}{12}\)

\(\dfrac{1}{4}-\dfrac{1}{5}=\dfrac{5}{20}-\dfrac{4}{20}=\dfrac{1}{20}\)

\(3-\dfrac{1}{3}=\dfrac{3}{1}-\dfrac{1}{3}=\dfrac{3}{3}-\dfrac{1}{3}=\dfrac{2}{3}\)

Bài 6 : Rút gọn rồi tính 

\(a,\dfrac{5}{10}=\dfrac{1}{2}\)

\(\dfrac{1}{2}-\dfrac{2}{15}=\dfrac{15}{30}-\dfrac{4}{30}=\dfrac{11}{30}\)

\(b,\dfrac{5}{20}=\dfrac{1}{4}\)

\(\dfrac{1}{4}-\dfrac{1}{9}=\dfrac{9}{36}-\dfrac{4}{36}=\dfrac{5}{36}\)

\(c,\dfrac{6}{18}=\dfrac{1}{3}\)                  \(\dfrac{6}{24}=\dfrac{1}{4}\)

\(\dfrac{1}{3}-\dfrac{1}{4}=\dfrac{4}{12}-\dfrac{3}{12}=\dfrac{1}{12}\)

\(d,\dfrac{3}{12}=\dfrac{1}{4}\)

\(\dfrac{5}{9}-\dfrac{1}{4}=\dfrac{20}{36}-\dfrac{9}{36}=\dfrac{11}{36}\)

1. Who are we going to visit next week?

2. How is the weather in the summer?

3. Who is my sister playing badminton with?

4. What do you had for dinner?

5. How did he go to HCM?

6. Where did you stay in London?

I.Make questions for the underlined words:

1.We are going to visit our uncle next week.

-> What are you going to do next week?

2.It is hot in the summer.

-> What is the weather like in the summer?

3.My sister is playing badminton with Jonh.

-> Who is your sister playing badminton with?

4.I had fish and chips for dinner.

-> What did you have for dinner?

5.He went to HCM by plane.

-> How did he go to HCM?

6.In London we stayed at Grand Hotel.

-> Where did you stay in London?

1 => Who are we going to visit next week?

2 => How is the weather in the summer?

3 => Who is my sister playing badminton with?

4 => What do you have for dinner?

5 => How did he go to HCM?

6 => Where did you stay in London?

Lớp đó có số HS nam là

\(40.45\%=18\) (HS)

Lớp đó có số HS nữ là

\(40-18=22\) (HS)

Số học sinh nam:

40 x 45% = 18 (học sinh)

Số học sinh nữ:

40 - 18 = 22 (học sinh)

                                                          Bài giải

            Lớp học đó có số học sinh nam là :40 x 45 = 18(học sinh nam)

            Lớp học đó có số học sinh nữ là:40 - 18 = 22 (học sinh nữ)

                         Đ/S :22 học sinh nữ

Bài 2:

a: \(=\dfrac{3}{5}\cdot\dfrac{6}{7}=\dfrac{18}{35}\)

b: =3/5+8/25

=15/25+8/25

=23/25

Bài 3:

a: =>x=2/3*2/5=4/25

b: =>x=4/9*2/3=8/27