Hello everyone, today our group will present one of the most useful inventions in the classroom. It is a smartphone. It is small and portable so you can bring it to school. Smartphones are cheaper than laptops, too. Smartphones give students access to tools and apps that can help them complete and stay on top of their classwork. Furthermore, smartphones help students find more information, let them research more about a topic while having class discussions. I think smartphones are a useful invention that makes our school work become easier if we use it efficiently in class.

cảm ơn nha

Hello everyone! My name is ...... Today I will tell you about inventions. Inventions are the solutions to our problems because they make our lives easier. Look at this invention! It’s light. You use electric lights to see in the dark. You use it when the sky is dark. Electric lights are the most necessary invention. If our life didn't have lights, it would be dark at night, and people wouldn’t see anything making our work invalid. Look at this invention! It’s a clock. It is used to watch time and help us not be late. You use it when you want to know the meeting time. The clock is a time-measuring device, it helps people wake up from a sleep. If people didn’t invent clocks we wouldn’t know if it was morning, afternoon, or evening. Look at this invention! It’s a computer. You use it to surf the internet and read the news. You use it when you want to chat with your friends or watch some interesting videos from everybody on YouTube. Inventors need to have intelligent brains and creativity, you also have a special talent. My favorite inventor is Thomas Edison. Thank you for listening class.

n=1 nhé bạn vì2*1+1=3 là số nguyên tố ; 9*1+4=13 là snt

vậy n=1 . cho mk 1 ticknhes 

Lời giải:
Gọi $d=ƯCLN(2n+1, 9n+4)$

$\Rightarrow 2n+1\vdots d; 9n+4\vdots d$

$\Rightarrow 9(2n+1)-2(9n+4)\vdots d$

$\Rightarrow 1\vdots d\Rightarrow d=1$
Vậy $2n+1, 9n+4$ nguyên tố cùng nhau với mọi $n$

$\Rightarrow$ mọi số tự nhiên $n$ đều thỏa mãn yêu cầu.

help mk vs

D.meat

Số viên bi ở hộp thứ hai sau khi có thêm 4 viên bi:

9 × 2 = 18 (viên)

Số viên bi ở hộp thứ hai lúc đầu:

18 - 4 = 14 (viên)

Số viên bi hộp thứ hai nhiều hơn hộp thứ nhất:

14 - 9 = 5 (viên)

KO CM DC VÌ KO CÓ SỐ NÀO *3 =22

Không đủ cơ sở để chứng minh bạn nhé.

3 MB = 3 . 1024 = 3072 KB

1MB=1024KB nên 3MB=1024.3=3072

Số thóc ở kho A lúc sau:

(145 - 15) : 2 = 65 (tấn)

65 tấn thóc ở kho A lúc sau so với lúc đầu:

1 - 1/6 = 5/6

Số thóc ở kho A lúc đầu:

65 : 5/6 = 78 (tấn)

Số thóc ở kho B lúc đầu:

145 - 78 = 67 (tấn)

giúp mình với mình đang cần gấp !!!!!!!