By the end of this century, we will have to explore the Moon to find important minerals. It will be dangerrous for people so we will use robots instead of humans. It won't be very expensive because robots won't need money, food, ari and water. They will only use solar energy. Robots will get minirals from the Moon and they will bring them back to the Earth

My school is between a post office and a library

chiều rộng bằng chiều dài ư????

What(Wh):cái gì

I want to buy a few sugar =>I want to buy a little sugar

Chưa thi xong lấy đâu ra điểm mà điểm danh học sinh giỏi.

A = (1 -1/2) + (1 - 1/6) + (1 - 1/12)  + (1 - 1/20 ) + ...+ (1 - 1/ 90)

= (1+1+1+1+1+1+1+1+1) - ( 1/2 - 1/6 - 1/12 - 1/ 20 - ...- 1/90)\(=9-\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{9.10}\right)=9-\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{9}-\frac{1}{10}\right)\)\(=9-\left(1-\frac{1}{10}\right)=\frac{81}{10}\)

làm sai bỏ qua cho mk nhá...