1.5x105、2.33x0.5x4、1.2x2.5+0.8x2.5这三个用简便算法怎么算?

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

1.5x105
=1.5×100+1.5×5
=150+7.5
=107.5
2.33x0.5x4
=2.33×（0.5×4）
=2.33×2
=4.66
1.2x2.5+0.8x2.5
=2.5×（1.2+0.8）
=2.5×2
=5

1.5x105
1.2x2.5+0.8x2.5
=2.5×（1.2+0.8）
=2.5×2
=5 =1.5×(100+5)
=150+7.5
=157.5
2.33x0.5x4
=2.33×（0.5×4）
=2.33×2
=4.66