Відповідь:

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Покрокове пояснення:

1) 6 4/9+3 5/9= (6+3) + (4/9 + 5/9)=9 9/9=10

2) 10 11/19+5 14/19= (10 + 5) + (11/19+14/19)=15 25/19= 16 6/19

3) 1 5/8+3 7/8=(1+3)+(5/8+7/8)=4 12/8=5 4/8

4) 1 - 3/11=11/11 - 3/11=8/11

5) 1 - 13/40=40/40 - 13/40=27/40

6) 4 - 1 4/7=28/7 - 11/7=17/7 = 2 3/7

7) 10 - 9 3/10= 100/10 - 93/10=7/10

8) 5 2/7 - 2 5/7=37/7 - 19/7=18/7 = 2 2/7

9) 14 6/20 - 8 12/20=286/20 - 172/20=114/20 = 57/10 = 5 7/10

10) 8 3/14 - 5 9/14=115/14-79/14= 36/14 = 18/7 = 2 4/7

11) 7 10/21 - 4 16/21=57/21= 19/7 = 2 5/7

12) 14 8/31 - 6 8/31= (14-6)+(8/31 - 8/31)= 8