540.

1) 9/10 * 20/27 + 5/16 : 10/24 - 5/9 * 1 7/20 = 2/3

1) 9/10 * 20/27 = 1/1 * 2/3 = 2/3

2) 5/16 : 10/24 = 5/16 * 24/10 = 1/4 * 6/2 = 1/2 * 3/2 = 3/4

3) 5/9 * 1 7/20 = 5/9 * 27/20 = 1/1 * 3/4 = 3/4

4) 2/3 + 3/4 - 3/4 = 2/3

2) 69/70 * 7/23 - 4/25 : 4/5 + 3/5 * 25/36 = 1/2

1) 69/70 * 7/23 = 3/10 * 1/1 = 3/10

2) 4/25 : 4/5 = 4/25 * 5/4 = 1/5

3) 3/5 * 25/36 = 1/1 * 5/12 = 5/12

4) 3/10 - 1/5 + 5/12 = 18/60 - 12/60 + 24/60 = 30/60 = 1/2 = 0,5

3) 120/169 * 13/60 + 200/243 : 100/81 - 1/13 * 10 = - 2/39

1) 120/169 * 13/60 = 2/13 * 1/1 = 2/13

2) 200/243 : 100/81 = 200/243 * 81/100 = 2/3

3) 1/13 * 10/1 = 10/13

4) 2/13 + 2/3 - 10/13 = 3/39 + 25/39 - 30/39 = -2/39

4) 125/147 * 21/50 - 70/119 * 17/210 - 3/14 * 7/9 = 1/7

1) 125/147 * 21/50 = 5/7 * 1/2 = 5/14

2) 70/119 * 17/210 = 1/7 * 1/3 = 1/21

3) 3/14 * 7/9 = 1/2 * 1/3 = 1/6

4) 5/14 - 1/21 - 1/6 = 15/42 - 2/42 - 7/42 = 6/42 = 1/7

541.

1) 1 2/9 : 3 2/3 + 4 2/5 : (7/10 + 2 3/5) - (3/17 - 1 16/17 : 11) = 1 2/3

1) 1 2/9 : 3 2/3 = 11/9 : 11/3 = 11/9 * 3/11 = 1/3

2) 7/10 + 2 3/5 = 7/10 + 2 6/10 = 2 13/10 = 3 3/10

3) 4 2/5 : 3 3/10 = 22/5 : 33/10 = 22/5 * 10/33 = 2/1 * 2/3 = 4/3 = 1 1/3

4) 1 16/17 : 11 = 33/17 * 1/11 = 3/17

5) 3/17 - 3/17 = 0

6) 1/3 + 1 1/3 - 0 = 1 2/3

2) 5/6 + 2 3/4 : 4 8/9 * 2 2/3 - 1 2/3 + (5/38 * 1 1/3 - 10/57 = 2/3

1) 2 3/4 : 4 8/9 = 11/4 : 44/9 = 11/4 * 9/44 = 1/4 * 9/4 = 9/16

2) 9/16 * 2 2/3 = 9/16 * 8/3 = 3/2 = 1 1/2

3) 5/38 * 1 1/3 = 5/38 * 4/3 = 5/19 * 2/3 = 10/57

4) 10/57 - 10/57 = 0

5) 5/6 + 1 1/2 - 1 2/3 = 5/6 + 1 3/6 - 1 4/6 = 4/6 = 2/3