Помагите математика 6класс

3 - 2/5 * 3 1/3 = 3 - 2/5 * 10/3 = 3 - 2/1 * 2/3 = 3 - 4/3 = 9/3 - 4/3 = 5/3 - 3 : 5 1/4 - 2 1/2 : 7/8 = - 3 : 21/4 - 5/2 : 7/8 = - 3 * 4/21 - 5/2 * 8/7 =  = - 4/7 - 20/7 = - 24/7 = - 3 3/7 7/8 * 2 2/3 + (- 5/6) : 2 1/7 = 7/8 * 8/3 + (- 5/6) : 15/7 = 7/3 + (- 5/6) * 7/15 =  = 7/3 + (- 7/18) = 7/3 - 7/18 = 42/18 - 7/18 = 35/18 1/5 - ( 1 1/2 - 1 2/7 * 7/18) = 1/5 - (1 1/2 - 9/7 * 7/18) = 1/5 - (1 1/2 - 1/2) = 1/5 - 1 = 1/5 - 5/5 = - 4/5