7 2/3 + (6 - 2 4/7) : 2 4/7 - 4,5 = 4,5

1) 6 - 2 4/7 = 6/1 - 18/7 = 42/7 - 18/7 = 24/7 = 3 3/7

2) 3 3/7 : 2 4/7 = 24/7 : 18/7 = 24/7 * 7/18 = 4/3 = 1 1/3

3) 7 2/3 + 1 1/3 = 8 3/3 = 9

4) 9 - 4,5 = 4,5