Question

初一数学上册导学案有理数的加法2课后反思

Answer 1

(1）[（+1）+（+2）+（-3）+（-4）]+[（+5）+（+6）+（-7）+(-8) ] …[（+97）+（+98）+（-99）+（-100）]

= -4 * (100/4)

= -100

每四个一组 和为-2

(2) [(+ 1 ) +(-3)] +[(+2)+（-4）]+ .+[(+98)+(-100)]

= -2 * (100/2) =-100

(3) (1+3+5+..99)-(2+4+6+...100) = -100