6.7×2.34-3.4×0.67=6.7×2.34-0.34×6.7 (变一变,就简便)=6.7×(2.34-0.34)=6.7×2=13.4
6.7×2.34-3.4×0.67=6.7×2.34-0.34×6.7=6.7×(2.34-0.34)=6.7×2=13.4
6.7×2.34-3.4×0.67=6.7×2.34-0.67×10×0.34=6.7×(2.34-0.34)=6.7×2=13.4