数学简便运算.85×99
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数学简便运算.85×99
数学简便运算.85×99
数学简便运算.85×99
85×99
=85×(100-1)
=85×100-85
=8500-85
=8415
85×99
=85×(100-1)
=85×100-85
=8415
85×99
=85×(100-1)
=85×100-85×1
=8500-85
=8500-(100-15)
=8500-100+15
=8400+15
=8415
85×(99+1)-85
85*99
=85*(100-1)
=85*100-85
=8500-85
=8415
8415
85x(100-1)=85x100-85x1=8500-85=8415