Question

A=1-2+3-4+5-6+....+199-200

 

Answer 1

A=(1-2)+(3-4)+(5-6)+.....+(199-200)

A=(-1)+(-1)+(-1)+....+(-1)

       100 số (-1)

A= (-1).100

A=(-100)

Answer 2

A = 1 - 2 + 3 - 4 + 5 - 6 + ....+ 199 -200

A = ( 1-2 ) + (3-4 ) + ( 5 - 6 ) +....+ (199-200)

A = (-1)     +       ( -1 )  +( -1 ) +...+ (-1)

A = ( -1).100

A= ( -100)