①506-397②323-189③467+997④987-178-222-390.-数学

题目简介

①506-397②323-189③467+997④987-178-222-390.-数学

题目详情

①506-397  ②323-189  ③467+997  ④987-178-222-390.
题型:解答题难度:中档来源:不详

答案

①506-397 
=506-400+3,
=106+3,
=109;
 ②323-189 
=323-200+11,
=123+11,
=134;
③467+997
=467+1000-3,
=1467-3,
=1464;

④987-178-222-390
=987-(178+222)-390,
=987-400-400+10,
=197;

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