23×98+2×77×4×9简便方法1

如题所述

第1个回答  2015-04-21
23×98+2×77×4×9
=(100-77)x(100-2)+2×77×4×9
=10000-200-77x100+77x2+2×77×4×9
=9800-77x(100-2-2×4×9)
=9800-77x【100-2-72】
=9800-77x26
=9800-7x11x2x13
=9800-7x2x(10+1)x(10+3)
=9800-7x2x(100+40+3)
=7x2x700-7x2x143
=7x2x557
=7x2x(500+50+5+2)
=7x2x500+7x2x50+7x2x5+7x2x2)
=7000+700+70+28
=7798本回答被网友采纳
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