10.1x8.2
=(10+0.1)x8.2
=10x8.2+0.1x8.2
=82+0.82
=82.82
简便运算
要多练习 揣摩
如 2x5=10
4x25=100
8x25=200
8x125=1000
低位相同
103-3=100
1994-94=1900
本题10.1 可以分成 10+0.1,或因为10.1x8=80.8,不用 进位,8.2分成 8+0.2
10.1x8.2
=(10+0.1)x8.2
=10x8.2+0.1x8.2
=82+0.82
=82.82
huo
10.x8.2
=10.1x(8+0.2)
=10.1x8+10.1x0.2
=80.8+2.02
=82.82