6.8x3.3＋6.8x6.7=6.8x（3.3+6.7）=6.8x10=68请采纳！
原式=6.8×（3.3+6.7）=6.8×10=68
6.8*（3.3+6.7）=6.8*10=68
6.8x3.3+6.8x6.7=6.8x(3.3+6.7)=6.8x10=68
