计算
-{-【-(-5)】}
=-{-[+5]}
=-[-5]
=5
-{+【-(+5)】}
=-{+[-5]}
=-[-5]
=5
(-1)+(+2)+(-3)+(+4)+...+(-41)+(+42)
=(-1+2)+(-3+4)+...+(-41+42)
=1+1+.+1,(共21个)
=21
丨1/3-1/2丨+丨1/4-1/3丨+丨1/5-1/4丨+...+丨1/10-1/9
=1/2-1/3+1/3-1/4+1/4-1/5+.+1/9-1/10
=1/2-1/10
=2/5
计算
-{-【-(-5)】}
=-{-[+5]}
=-[-5]
=5
-{+【-(+5)】}
=-{+[-5]}
=-[-5]
=5
(-1)+(+2)+(-3)+(+4)+...+(-41)+(+42)
=(-1+2)+(-3+4)+...+(-41+42)
=1+1+.+1,(共21个)
=21
丨1/3-1/2丨+丨1/4-1/3丨+丨1/5-1/4丨+...+丨1/10-1/9
=1/2-1/3+1/3-1/4+1/4-1/5+.+1/9-1/10
=1/2-1/10
=2/5