Question

1+2-3-4+5+6-7-8+....+97+98-99-100

Answer 1

Ta có : 1+ 2 - 3 - 4 + 5 + 6 - 7 - 8 +...........+97 + 98 - 99 - 100

= ( 1 + 2 - 3 - 4 ) + ( 5 + 6 -7 -8)+........+( 97 + 98 - 99 - 100 ) ( 25 nhóm )

= ( - 4 ) + ( -4 ) +...................+ ( -4) ( 25 số )

= ( -4 ) . 25

= - 100

Answer 2

1+2-3-4+5+6-7-8+...+97+98-99-100

= (1+2-3-4)+(5+6-7-8)+...+(97+98-99-100)

=(-4)+(-4)+...+(-4)

=(-4).25=-100