3 3 5 7 13 23. 7 1/2:2 1/2×3 2/3-5 1/4×5/13×(1 1/2). 9 1 9 2-19 1 9. 2 1/3 * 5/14 : 1 1/9. 2 1/3:(5/8-8/4)-2*1 3/7