=15.6*13.1—15.6*1—15.6*2.1
=15.6*(13.1—1—2.1)
=15.6*10
=156
=15.6×13.1-15.6×1-15.6×2.1
=15.6×(13.1-1-2.1)
=15.6×10
=156
满意望采纳
15.6x13.1一15.6x1一15.6×2.1=
15.6x(13.1-1+2.1)=15.6x10=156
15.6x13.1一1.56x10一0.156×210
=15.6×13.1-15.6×1-15.6×2.1
=15.6×(13.1-1-2.1)
=15.6×10
=156
=15.6×13.1-15.6-15.6×2.1
=15.6×(13.1-1-2.1)
=15.6×10
=156