3 1/4*4=13/4×4=13;
10*5 2/5= 10×27/5=2×27=54;
3 5/16 * 1=3_5/16;
3*5 1/3=3×16/3=16;
4 1/2: 6 3/4=9/2÷27/4=9/2×4/27=9×4/2×27=2/3;
2 1/2*3 1/15=5/2×46/15=5×46/2×15=23/3=7_2/3;
4/9 * 3 3/4=4/9×15/4= 4×15/9×4=5/3=1_2/3;
1 6/7 * 3 5/10=13/7×3_1/2= 13/7×7/2=13×7/7×2=13/2=6_1/2;
10:3 1/3=10÷10/3=10×3/10=3