3/11 * 1/4. 5/6 * 4/7 3/7 * 2/3 7/9 * 3/5 7/8 * 12/17

3/11*1/4=3/44 5/6*4/7=5/3*2/7=10/21 3/7*2/3=1/7*2/1=2/7 7/9*3/5=7/3*1/5=7/15 7/8*12/17=7/2*3/17=21/34