Question

15.6×13.1-15.6-15.6×21的简便运算

Answer 1

15.6×13.1-15.6-15.6×21
=15.6×（13.1-1-21）
=15.6×（-8.9）
=-15.6×10+15.6×1+15.6×0.1
=-156+15.6+1.56
=-156+17.16
=-138.84

Answer 2

15.6-13.1-15.6-15.6×2.1
=15.6×（13.1-1-2.1）
=15.6×10
=156