解: 4/9×3+2/9×2+1/9×2
=2/9*(2*3+2+1)
=2/9*(6+3)
=2/9 *9
=2
4/9×3+2/9×2+1/9×2=1/9×4×3+1/9×2×2+1/9×2=1/9×（12+4+2）=1/9×18=2
=4/9×3+2/9×2+2/9×1=4/9×3+2/9×(2+1)=4/9×3+2/9×3=3×(4/9+2/9)=3×2/3=2
