Question

Tính tổng

2 - 4 + 6 - 8 + ... + 48 - 50 

Answer 1

2 - 4 + 6 - 8 + ... + 48 - 50

= (-2) + (-2) + ... + (-2)

= [(50 - 2) : 2 + 1] . (-2)

= [48 : 2 + 1] . (-2)

= 25 . (-2)

= -50

Answer 2

=(2-4)+(6-8)+...+(48-50)

=(-2)+(-2)+...+(-2) (co 25 so -2)

=(-2)x25

=-50

tk nha

Answer 3

2 - 4 + 6 - 8 + ........ + 48 - 50

= ( - 2 ) + ( - 2 ) + ......... + ( - 2 )

= [( 50 - 2 ) : 2 + 1 ] . ( - 2 )

= [48 : 2 + 1] . ( - 2 )

= 25 . ( - 2 )

= - 50