![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 23 + (-77) + (-23) + 77 =
[23 + (-23)] + [(-77) + 77]
= …0+0=0……
b) (-2 020) + 2 021 + 21 + (-22)
=[(-2 020) + 2 021] + [21 + (-22)]
= …1……+ (-1)……..
= 0.
![](https://rs.olm.vn/images/avt/0.png?1311)
256 ÷ 81 × 2 + 22 =50
256 x 2: 81 + 22 = 50
512 : 81 = 50 - 22
512/81 = 28
Vô lí
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=\dfrac{21}{22}+\dfrac{22}{23}=\dfrac{967}{506}>1\)
\(B=\dfrac{21+22}{22+23}=\dfrac{43}{45}< 1\)
Vậy \(A>B\)
\(\dfrac{21}{22}\) > \(\dfrac{21}{22+23}\)
\(\dfrac{22}{23}\) > \(\dfrac{22}{22+23}\)
Cộng vế với vế ta có:
A = \(\dfrac{21}{22}\) + \(\dfrac{22}{23}\) > \(\dfrac{21+22}{22+23}\) = B ⇒ A > B
![](https://rs.olm.vn/images/avt/0.png?1311)
a) (-42) + 71 + (-58) + 29
= (71 + 29) - (42 + 58)
= 100 - 100
= 0
b) (42.84 + 42.16) - (25.47 + 25.53)
= 42.(84 + 16) - 25.(47 + 53)
= 42.100 - 25.100
= 100.(42 - 25)
= 100.17
= 1700
c) 45 - {61 - [2.(2³ + 4.3) + (256 - 246).2¹^¹⁹⁹⁹]}
= 45 - {61 - [2.(8 + 12) + 10.2¹]}
= 45 - [61 - (2.20 + 10.2)]
= 45 - [61 - (40 + 20)]
= 45 - (61 - 60)
= 45 - 1
= 44
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(3.5^2+15.2^2-26\div2\)
= 3.25 + 15.4 - 13
= 75 + 60 - 13
= 135 - 13
= 122
b) \(5^3.2-100\div4+2^3.5\)
= 125.2 - 25 + 8.5
= 250 - 25 + 40
= 225 + 40
= 265
c)\(6^2\div9+50.2-3^3.33\)
= 36 : 9 + 100 - 9.33
= 4 + 100 - 297
= 104 - 297
= -193
d)\(3^2.5+2^3.10-81\div3\)
= 9.5 + 8.10 - 27
= 45 + 80 - 27
= 125 - 27
= 98
e) \(5^{13}\div5^{10}-25.2^2\)
= 53 - 25.4
= 125 - 100
= 25
f) \(20\div2^2+5^9\div5^8\)
= 20 : 4 + 5
= 5 + 5
= 10
![](https://rs.olm.vn/images/avt/0.png?1311)
Đề bài yêu cầu gì?
A=\(2+2^2+2^3+...+2^{56}\)
2.A=\(2^2+2^3+2^4+...+2^{57}\)
2.A-A=\(2^{57}-2\)
A=\(2^{57}+2\)
(SAI THÔI NHÉ)