Giải:

Khi người ta làm con đường bao quanh cái hồ hình tròn thì được một hình tròn mới có bán kính là:

4 + 1 = 5 (m)

Diện tích của toàn bộ cái hồ và con đường chính bằng diện tích của hình tròn mới và bằng:

        5 x 5 x 3,14 = 78,5(m²)

Diện tích cái hồ là:

     4 x 4 x 3,14  = 50,24 (m²)

Diện tích lối đi là: 78,5 - 50,24  = 28,26(m²)

Đáp số: 28,26m²

28,26m2 bạn nhé

My family is a small family in a rural area. My family has 4 people. That’s my dad, my mom, my sister and me. Because I live in the countryside, my family’s main occupation is farming. My parents will wake up very early to go to the fields. The field is very wide and has many trees. My parents grow a lot of trees. Every day, after going to school I would water those trees. When the harvest comes, I often help my dad. After the harvest, my parents will sell the results we get. The money earned will help my family support a living and help me and my sister go to school. Farming is very tiring but very fun. I watched the trees grow day by day. I love my family’s work.

Em cần giúp gì nhỉ

Subject: My Favorite School Activities

Hi Thanh

I hope this email finds you well. I wanted to share with you some of my favorite activities at school. They are always the highlight of my week!

One of my favorite activities is the library time. I enjoy spending time there, reading interesting books and discovering new knowledge. It’s such a peaceful and inspiring place. Another activity I love is our computer class, where I get to practice programming and create small projects. It’s so exciting to see ideas come to life through code!

I also enjoy participating in group activities, like team quizzes and sports. It’s great to work together with friends and learn from each other. Recently, we had a fun class competition, and our team did quite well, which made it even more special.

What about you? Do you have any favorite activities at your school? I’d love to hear about them.

Looking forward to your reply!

        Name

  Bao Nguyen

\(21\times136-21\times36+32\\ =21\times\left(136-36\right)+32\\ =21\times100+32\\ =2100+32\\ =2132\)

    21 x 136 - 21  x 36 + 32

= 21 x (136 - 36) + 32

= 21 x 100 + 32

= 2100 + 32

= 2132