1 4/9 * 1 5/13 - 2 1/12 * 4/15 = 1 4/9
выражением:
= 13/9 * 18/13 - 25/12 * 4/15 =
= 2 - 5/9 = 1 4/9
по действиям:
1) 1 4/9 * 1 5/13 = 13/9 * 18/13 = (13*18)/(9*13) = 2/1 = 2
2) 2 1/12 * 4/15 = 25/12 * 4/15 = (25*4)/(12*15) = (5*1)/(3*3) = 5/9
3) 2 - 5/9 = 18/9 - 5/9 = 13/9 = 1 4/9