55. Вычислите значение выражения наиболее удобным способом:

1) 3/8 + 5/9 + 5/8 + 4/9 = (3/8 + 5/8) + (5/9 + 4/9) = 1 + 1 = 2.
2) 4/15 + 3/7 + 11/15 + 6/7 = (4/15 + 11/15) + (3/7 + 6/7) = 1 + 1 = 2.
3) 5⅓/8 + 3⅕/7 + 1⅒/5 + 4⅕/8 = (5⅓/8 + 4⅕/8) + 3⅕/7 + 1⅒/5 = 9⅓/8 + 3⅕/7 + 1⅒/5 = 1⅓/8 + 3⅕/7 + 1⅒/5 = 1.375 + 3.714 + 1.4 = 6.489.