化简相反数

题目

化简相反数
①-[-(-2/3)] ②-[+(-1又1/3)]③-[-（-5/3）]④-{-[+（-2.5）]

答案

①-[-(-2/3)]
=-[2/3]
=-2/3.
②-[+(-1又1/3)]
=-[-4/3]
=4/3,
③-[-（-5/3）]
=-[5/3]
=-5/3.
④-{-[+（-2.5）]
=-{-[-2.5]}
=-{2.5}
=-2.5