Пошаговое объяснение:

4 7/19+3 18/19=(4+3)+(7/19+18/19)=

=7+25/19=7+1 6/19=8 6/19

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

=4+3/2= 4+1 1/2=5 1/2

1-4/11= 11/11-4/11=7/11

1-6/13= 13/13-6/13=7/13

5-17/19 =4 19/19-17/19= 4 2/19

14-139/243= 13 243/243-139/243=

= 13 104/243