1) 9 3/5 * 10/21=48/5 * 10/21=16/1 * 2/7=32/7=4 4/7;
2) 3 11/12 * 9/94=47/12 * 9/94=1/4 * 3/2=3/8;
3) 1 5/7 * 6 1/8=12/7 * 49/8=3/1 * 7/2=21/2=10 1/2;
4) 3 5/9 * 5 1/4=32/9 * 21/4=8/3 * 7/1=56/3=18 2/3;
5) 1 13/15 * 5/8 * 2 2/7=28/15 * 5/8 * 16/7=4/3 * 1/1 * 2/1=8/3=2 2/3;
6) 2 1/4 * 16/27 * 4 1/3=9/4 * 16/27 * 13/3=1/1 * 4/3 * 13/3=52/9=5 7/9.