7/18×3/4+11/4×3/18
=3/18×3/4+11/4×3/18+4/18×3/4
=3/18×(3/4+11/4)+1/6
=1/6×14/4+1/6
=1/6×(14/4+1)
=1/6×18/4
=3/4
或者
=7/18×3/4+(2+3/4)×3/18
=3/4×(7/18+3/18)+2×3/18
=3/4×5/9+1/3
=5/12+1/3
=3/4
7/18x3/4+11/4x3/18
=7/18x3/4+3/4x11/18
=(7/18+11/18)x3/4
=1x3/4
=3/4
7/18*3/4+11/4*3/18
=3/18(7/4+11/4)
=3/18*18/4
=3/4