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怎样简便就怎样算256+199102×4.57.8×6.9+2.2×6.924×2.5.

题目详情
怎样简便就怎样算
256+199                                  
102×4.5
7.8×6.9+2.2×6.9                                  
24×2.5.
▼优质解答
答案和解析
(1)256+199,
=256+(200-1),
=256+200-1,
=455;

(2)102×4.5,
=(100+2)×4.5,
=450+9,
=459;

(3)7.8×6.9+2.2×6.9,
=(7.8+2.2)×6.9,
=10×6.9,
=69;

(4)24×2.5,
=6×4×2.5,
=6×(4×2.5),
=6×10,
=60.