4,2:(2,25-1целая7/8*3целых1/3)

4,2:(2,25-1целая7/8*3целых1/3) = - 1,05                                                              5 * 5             251)  1целая7/8*3целых1/3 = 15/8 * 10/3 = -------------- = ---------- = 6,25                                                                4 * 1             42) 2,25 - 6,25 = - 43) 4,2 :(-4) = - 1,05