3-1 2/5 2/3*3/4 4/5*5 5/9*1/5 1 1/3*3/4 2 1/4*1 1/3
В 4 , 5 ,6сокращение, если что
1) 3 - 2/5 = 2 * 5/5 - 2/5 = 2 3/5 2) 2/3 * 3/4 = 1/2 3)4/5 * 5 = 20/5 = 4 4) 5/9 * 1/5 = 1/9 5)11/3 * 3/4 = 11/4 = 2 3/4 6)21/4* 11/3 = 7/4 * 11 = 77/4 = 19 1/4