№342
1) 15 4/9 - 4 4/9 * 3 3/8 = 15 4/9 - 40/9 * 27/8 = 15 4/9 - 15 = 4/9
2) 81/88 * (6 - 1 13/15* 1 19/21) = 81/88 * (6 - 3 5/9) = 81/88 * 2 4/9 = 81/88 * 22/9 = 9/4 = 2 1/4
3) (5 1/16 - 1 1/8) * (5/6 + 3/14) = (5 1/16 - 1 2/16) * (35/42 + 9/42) = 3 15/16 * 44/42 = 63/16 * 44/42 = 4 1/8
4) 5 1/16 - 1 1/8 * (5/6 + 3/14) = 5 1/16 - 1 1/8 * 1 1/21 = 5 1/16 - 1 5/28 = 3 99/112
№343
66 * 5/6 = 55 5/6 км