1) 7/9* (3 5/14 - 2 3/14) = 7/9 * 1 2/14 = 7/9 * 1 1/7 = 7/9 * 8/7 7 сокращаем = 8/9
2) точно в задании 1/58 ? а не 1/8?
3) выносим за скобки 1 3/5 * ( 3/4 + 11/8 + 3/2) = 8/5 * 6/8+11/8-12/8 = 8/5 * 5/8 =1
4) 0,3* ( 3 9/14 -1 10/21 + 1 1/6)= 3/10* (153/42- 62/42 - 49/42) = 3/10 * 140/42=
3/10 * 3 14/42= 3/10 * 3 1/3 = 3/10 * 10/3 = 1