50×27×2
=50×2×27
=100×27
=2700
102×73
=(100+2)×73
=100×73+2×73
=7300+2×(70+3)
=7300+2×70+2×3
=7300+140+6
=7446
55×99+55
=55×99+55×1
=55×(99+1)
=55×100
=5500
164×17+36×17
=(164+36)×17
=200×17
=3400