2.4×1.25=0.3×（8×1.25）=0.3×10=3
=0.6×（4×1.25）=0.6×5=3
＝0.3X（8X1.25）＝0.3X10＝3
2.4x1.25=0.3*8*1.25=0.3*10=3
