2 2/11*1 3/8:3/4 11/23*3 2/7:5 1/2
2 2/11*1 3/8:3/4 24/11×11/8=3 3:3/4=3×4/3=4 11/23*3 2/7:5 1/2 11/23×23/7=11/7 11/7×2/11=2/7