102.36×49
=102.36×(50-1)
=5118-102.36
=5015.64
2.25×1.8+1.25×0.18
=0.18×(2.25x10+1.25)
=0.18×(22.5+1.25)
=0.18×23.75
=0.18×(25-1.25)
4.5-0.225
=4.275