有理数的加减运算1/2+(-2/3)-(-4/5)+(-1/2)

问题描述:

有理数的加减运算1/2+(-2/3)-(-4/5)+(-1/2)

1/2+(-2/3)-(-4/5)+(-1/2)
=1/2+(-1/2) +(-2/3)-(-4/5)
=0+(-2/3)-(-4/5)
=2/15

-4/5

1/2+(-2/3)-(-4/5)+(-1/2)=1/2-2/3+4/5-1/2=(1/2-1/2)+(4/5-2/3)=2/15

=2/15

1/2+(-2/3)-(-4/5)+(-1/2)
=1/2-2/3+4/5-1/2
=1/2-1/2+12/15-10/15
=(12-10)/15
=2/15