Question

98点6×98点6-98点5×98点七简便运算

98点6×98点6-98点5×98点七简便运算

Answer 1

98.6^2-98.5*98.7
=98.6^2-(98.6-0.1)(98.6+0.1)
=98.6^2-(98.6^2-0.1^2)
=98.6^2-98.6^2+0.01
=0.01

Answer 2

98点6×98点6-98点5×98点七
=98.6*98.6-98.5*98
=98.6*98.6-98.6*98+0.1*98
=98.6*【98.6-98】+9.8
=98.6*0.6+9.8
=100*0.6-1.4*0.6+9.8
=60+9.8-0.84
=69-0.04
=68.96
满意采纳