1.8*1.2=2.16,2.16+1.44=3.6,3.6+5.86=9.46
1.6*1.4、2.3*2.7……都可以用首位加1相乘的积=末位相乘的积。如:14*16=1*2+4*6=224
5.86+1.8*1.2+1.44
=5.86+1.8*1.2+1.2*1.2
=5.86+1.2*(1.8+1.2)
=5.86+1.2*3
=5.86+3.6
=9.46
计算器计算
5.86+1.8x1.2+1.44
=5.86+1.8x1.2+1.2×1.2
=5.86+(1.8+1.2)×1.2
=5.86+3x1.2
=5.86+3.6
=9.46
1.44=1.2*1.2
5.86+1.8*1.2+1.44
=5.86+1.8*1.2+1.2*1.2
=5.86+(1.8+1.2)*1.2
=5.87+3*1.2
=5.86+3.6
=9.46