A = \(\dfrac{101+100+98+97+...+3+2+1}{101-100+99-98+...+3-2+1}\) 

    = \(\dfrac{\left(101+1\right).101:2}{1+1+1+...+1}\) 

    = \(\dfrac{5151}{101}\) = 51

A=151

B=?

tích cho tui nhé

B=1+2-(3+4)+5+6-..-100+101
B=(3+11+19+...+195)-(7+15+...+199)+101

B=25.99-25.103+101

B=-100+101=1

Vậy B=1

a=151

B=1 nha

Xét tử ta có: 

\(101+100+99+98+...........+3+2+1\)

\(=1+2+3+..........+99+100+101\)

\(=\frac{101.102}{2}=5151\)

Xét mẫu ta có:

\(101-100+99-98+.......+3-2+1\)

\(=\left(101-100\right)+\left(99-98\right)+.......+\left(3-2\right)+1\)

\(=1+1+.......+1+1=51\)

\(\Rightarrow A=\frac{5151}{51}=101\)

Tính

(2^100+ phần sau là đề của bạn tự hiểu

2^100+2^101+2^102=2^100+101+102=2^303:(2^97+2^98+2^99)=2^303:(2^97+98+99)=2^303:2^294=2^303-294-2^9=512

Đề sai ko cậu?

đề sai bạn ơi

\(c,G=1-2-3+4+5-6-7+...+97-98-99+100\)

\(=\left(1-2-3+4\right)+\left(5-6-7+8\right)+...+\left(97-98-99+100\right)\)  (có tất cả \(100\div4=25\)cặp)

\(=0+0+...+0=0\)

\(d,H=2^{100}-2^{99}-2^{98}-...-2-1\)

\(\Rightarrow2H=2^{101}-2^{100}-2^{99}-...-2^2-2\)

\(=2^{101}-\left(2^{100}+2^{99}+...+2^2+2\right)\)

Đặt \(A=2^{100}+2^{99}+2^{98}+...+2^2+2\)

Tính được \(A=2^{101}-2\)

\(\Rightarrow H=2^{101}-\left(2^{101}-2\right)=2^{101}-2^{101}+2=2\)

\(e,I=2-5+8-11+...+98-101\)

\(=\left(2-5\right)+\left(8-11\right)+...+\left(98-101\right)\)  (có tất cả \(34\div2=17\)cặp)

\(=\left(-3\right)+\left(-3\right)+...+\left(-3\right)\)

\(=\left(-3\right).17=-51\)

Sửa lại phần d

\(d,H=2^{100}-2^{99}-2^{98}-...-2-1\)

\(=2^{100}-\left(2^{99}+2^{98}+2^{97}+...+2+1\right)\)

Đặt \(A=2^{99}+2^{98}+2^{97}+...+2+1\)

Tính \(A=2^{100}-2\)

\(\Rightarrow H=2^{100}-\left(2^{100}-2\right)=2^{100}-2^{100}+2=2\)