（1）3.8×6.7+3.3×3.8
=（6.7+3.3）×3.8
=10×3.8
=38；
（2）1.28×0.29-0.29×0.28
=（1.28-0.28）×0.29
=1×0.29
=0.29；
（3）101×4.8 
=（100+1）×4.8
=100×4.8+1×4.8
=480+4.8
=484.8．
（4）56×12.5×2
=7×（8×12.5）×2
=7×100×2
=1400．