70)
6/8 = 3/4; 12/56 = 3/14; 10/14 = 5/7; 2/7;
mcm = 4 * 7 = 28 ;
3/4 = 21/28; 3/14 = 6/28; 5/7 = 20/28; 2/7 = 8/28.
71)
27/12 = 9/4; 14/40 = 7/20; 75/45 = 15/9 = 5/3;
4/30 = 2/15;
mcm = 2^3 * 3^2 * 5 = 360;
9 /4 = 810/360; 7/20 = 126/360; 5/3 = 600 / 360; 2/15 = 48 /360.