Question

72乘二点零九减一点八乘73点六的简便计算

Answer 1

72X2.09 - 1.8X73.6 = 72X2.09 - 18X7.36 = 18X（4X2.09 - 7.36）=18X（8.36 - 7.36）= 18

Answer 2

72×2.09-1.8×73.6
=1.8×40×2.09-1.8×73.6
=1.8×83.6-1.8×73.6
=1.8×（83.6-73.6）
=1.8×10
=18