a   (221+23-58)-(58+221+23)

   =221+23-58-58-221-23

   =(221-221) + (23-23) +(-58-58)

   =-116

Ta có: \(S=\frac{1}{2^2}-\frac{1}{2^4}+\frac{1}{2^6}-\frac{1}{2^8}+\cdots+\frac{1}{2^{2002}}-\frac{1}{2^{2004}}\)

=>4S=\(1-\frac{1}{2^2}+\frac{1}{2^4}-\frac{1}{2^6}+\cdots+\frac{1}{2^{2000}}-\frac{1}{2^{2002}}\)

=>4S+S=\(1-\frac{1}{2^2}+\frac{1}{2^4}-\frac{1}{2^6}+\cdots+\frac{1}{2^{2000}}-\frac{1}{2^{2002}}+1-\frac{1}{2^2}+\frac{1}{2^4}-\frac{1}{2^6}+\cdots+\frac{1}{2^{2000}}-\frac{1}{2^{2002}}\)

=>5S=\(1-\frac{1}{2^{2002}}\)

=>5S<1

=>S<0,2

Đây có phải phân số đâu bạn?

\(126+(-20)+|124|-(-320)-|-150|\\=126-20+124+320+125\\=(320-20)+124+125+126\\=300+375\\=675\)

ko vt lại đề

mà cái này bấm máy tính là ra.........

\(126+\left(-20\right)+|124|-\left(-320\right)-|-150|\)

\(=126-20+124+320-150\)

\(=400\)

= 126 + ( - 20 ) + 124 - ( - 320 ) - 150

= ( 126 + ( - 20 ) ) + 124 - ( - 320 ) - 150

= 106 + 124 - ( - 320 ) - 150

=( 106 + 124 ) - ( - 320 ) -150

= 230 - ( - 320 ) - 150

= ( 230 - ( - 320 ) ) -150

= 550 - 150

= 400 

\(=100+124+320-150\)

\(=224+320-150\)

\(=544-150\)

\(=394\)

=126 + (-20) + 124 - (-320) - 15

= 106 + 124 - (-320) - 15

=   230 - (-320) -15

=  230 + 320 - 15

=  550 - 15

=   535