Question

A=1-3+5-7+........+97-99+101

Answer 1

A = 1 - 3 + 5 - 7 + ........ + 97 - 99 + 101 

A = ( 1 - 3 ) + ( 5 - 7 ) + ...... + ( 97 - 99 ) + 101

A =  ( -2 ) + ( -2 ) + ....... + ( -2 ) + 101

          25 số ( -2 )

A = ( -2 ) x 25 + 101

A = ( -50 ) + 101

A = 51

Answer 2

1-3+5-7+........+97-99+101

=(1-3)+(5-7)+........+(97-99)+101

= -2 + -2 + .......... + -2  + 101  ( 50 so hang -2 )

= -2 x 50  + 101

=          1

ks nha !!!

thank you very much !!!!

Answer 3

A = 1 - 3 + 5 - 7 + ... + 97 - 99 + 101

   = ( 1 - 3 ) + ( 5 - 7 ) + ... + ( 97 - 99 ) + 101

   = ( -2 ) + ( -2 ) + ... + ( -2 ) +101        ( Có 25 số -2 )

   = ( -50 ) + 101

   = 51

Vậy A = 51