Tính nhanh
A= 1 và 1/2+ 1 và 1/6+1 và 1/12+.....+1 và 1/380+1 và 1/420
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Exercise 1: Fill correct words in the blank
1. She feels tired. She should get some……rest………
2. Nam is sick and has a headache. He should…take medicine…………
3. I ate bad food yesterday. I had a …stomachache…………
4. He has a fever. He should ………see the doctor………
5. My brother often drinks cold water, so he has a……sore throat………….
1. They are going boating
2. I think they like that and it makes them relaxed
1.They are go boating.
2.Because they like that and the cool and quiet feeling.
\(\overline{ab7}\) x 3 + 70 = \(\overline{7ab}\)
(\(\overline{ab}\) x 10 + 7) x 3 + 70 = 700 + \(\overline{ab}\)
\(\overline{ab}\) x 30 + 21 + 70 = 700 + \(\overline{ab}\)
\(\overline{ab}\) x 30 + (21 + 70) = 700 + \(\overline{ab}\)
\(\overline{ab}\) x 30 + 91 = 700 + \(\overline{ab}\)
\(\overline{ab}\) x 30 + 91 - \(\overline{ab}\) = 700
(\(\overline{ab}\) x 30 - \(\overline{ab}\)) + 91 = 700
\(\overline{ab}\) x (30 - 1) + 91 = 700
\(\overline{ab}\) x 29 + 91 = 700
\(\overline{ab}\) x 29 = 700 - 91
\(\overline{ab}\) x 29 = 609
\(\overline{ab}\) = 609 : 29
\(\overline{ab}\) = 21