Question

(-1)+2+(-3)+4+(-5)+6+....+(-9)+10

Answer 1

Ta có: (-1) + 2 + (-3) + 4 +(-5) + 6 + .....+(-9) + 10

= ( 2 + 4 +6 +....+10) + ((-1) + (-3)+(-5)+.....+(-9))

= (10 + 2).5 + ((-9) + (-1)) . 5

= ( 12+ (-10)).5

= 2.5=10

Answer 2

Ta có: (-1) + 2 + (-3) + 4 +(-5) + 6 + .....+(-9) + 10

= ( 2 + 4 +6 +....+10) + [(-1) + (-3)+(-5)+.....+(-9)]

= (10 + 2).5 + ((-9) + (-1)) . 5

= [(12+ (-10)].5

= 2.5

=10

Answer 3

(-1)+2+(-3)+4+(-5)+6+(-7)+8+(-9)+10

= [(-1)+(-9)+10]+[2+8+(-3)+(-7)]+(4+6)+(-5)

= 0+0+10+(-5)

= 10+(-5)

= 5

Answer 4

(-1)+2+(-3)+4+(-5)+6+(-7)+8+(-9)+10

= [(-1)+2]+[(-3)+4]+[(-5)+6]+[(-7)+8]+[(-9)+10]

= 1+1+1+1+1

= 1 . 5

= 5