计算题,七年级-7-（-8）-（7又1/2）-（+9）+（-10）+11又1/21又1/2计算题,七年级-7-（-8）-（7又1/2）-（+9）+（-10）+11又1/21又1/2-2又5/6+3又1/12-4又19/20+5又1/30-6又41/42+7又1/56-8又71/72+9又1/90

Question

计算题,七年级-7-（-8）-（7又1/2）-（+9）+（-10）+11又1/2 1又1/2
计算题,七年级-7-（-8）-（7又1/2）-（+9）+（-10）+11又1/2
1又1/2-2又5/6+3又1/12-4又19/20+5又1/30-6又41/42+7又1/56-8又71/72+9又1/90

Answer 1

-7-(-8)-(7又1/2)-(+9)+(-10)+11又1/2
=-7+8+(-7又1/2)+(-9)+(-10)+11又1/2
=(8+11又1/2)+[ (-7)+(-7又1/2)+(-9)+(-10) ]
=19又1/2+(-26又1/2)
=-(26又1/2-19又1/2)
=-7
1又1/2-2又5/6+3又1/12-4又19/20+5又1/30-6又41/42+7又1/56-8又71/72+9又1/90
=(1+1/2)-(3-1/6)+(3+1/12)-(5-1/20)+(5+1/30)-(7-1/42)+(7+1/56)-(9-1/72)+(9+1/90)
=1+1/2-3+1/6+3+1/12-5+1/20+5+1/30-7+1/42+7+1/56-9+1/72+9+1/90
=(1-3+3-5+5-7+7-9+9)+(1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90)
=1+( 1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10 )
=1+(1 -1/10)
=1+ 9/10
=1又9/10