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怎样算简便就怎样算.278+598+122647-289-111287+198.

题目详情
怎样算简便就怎样算.
278+598+122 647-289-111 287+198.
▼优质解答
答案和解析
(1)278+598+122,
=278+122+598,
=400+598,
=998;

(2)647-289-111,
=647-(289+111),
=647-400,
=247;

(3)287+198,
=287+(200-2),
=287+200-2,
=487-2,
=485.