Question

2的倒數(shù)是________，-2.5的相反數(shù)是________；絕對(duì)值等于3的數(shù)是________．

Answer 1

    2.5    ±3
分析：絕對(duì)值相等且符號(hào)相反的兩個(gè)數(shù)互為相反數(shù)，兩個(gè)相乘等于1的數(shù)互為倒數(shù)，由此可得出答案．
解答：2的倒數(shù)為，-2.5的相反數(shù)為2.5，絕對(duì)值為3的數(shù)為±3．
故填：，2.5，±3．
點(diǎn)評(píng)：本題考查了倒數(shù)和相反數(shù)的定義，注意絕對(duì)值等于3的數(shù)有兩個(gè)．