1.5x105
=1.5×(100+5)
=150+7.5
=157.5
2.33x0.5x4
=2.33×2
=4.66
1.2x2.5+0.8x2.5
=0.3×4×2.5+0.2×4×2.5
=0.3×10+0.2×10
=3+2
=5