1) 7,8 * 4/13 - 61,5 / 13 3/2 + 198,8 = 78/10 * 4/13 - 615/10 / 29/2 + 198,8 = 12/5 - 123/29 +198,8 = 2,4 - 4 7/29 + 198,8 = 201,2 - 4 7/29 = 201 1/5 - 4 7/29 = (201 - 4) + (1/5 - 7/29) = 197 + (29/145 - 35/145) = 197 + (- 6/145) = 197 - 6/145 = 196 139/145
2) 19,25 * 5/11 + 5,76 * 5/12 - 13,009 = 1925/100 * 5/11 + 576/100 * 5/12 - 13,009 = 35/4 + 12/5 - 13,009 = 8,75 + 2,4 - 13,009 = 11,15 - 13,009 = - 1,859
3) 4,625 * 2 2/15 / 2,96 - 2 4/7 = 4 5/8 * 2 2/15 / 2,96 - 2 4/7 = 37/8 * 32/15 / 296/100 - 32/7 = 37/8 * 80/(37*3) - 32/7 = 10/3 - 32/7 = 70/21 - 96/21 = - 26/21 = 1 5/21
4) 30,25 / 4 5/7 / 1,05 - 2 1/6 = 30 1/4 / 4 5/7 / 105/100 = 121/4 / 35/7 21/20 121/
а вот подробное 60+24=84
84:12=7