5/8+1/4=,8-3,7=, 4/7*7/8=, 4целых2/7: 1целое1/7=, 4,8: (7+3в квадрате)=, 3/7m+2/7m+4/7m-2/7m. если. а) m=9/13,б)m=18

5/8 + 1/4 = 5/8 + 2/8 = 7/8
8 - 3,7 = 4,3
4/7 * 7/8 = (1*1)/(1*2) = 1/2
4 2/7 : 1 1/7 = 30/7 : 8/7 = 30/7 * 7/8 = (15*1)/(1*4) = 15/4 = 3 3/4
4,8 : (7 + 3 * 3) = 4,8 : 16 = 0,3
3/7m + 2/7m + 4/7m - 2/7m = 7/7m = m