Respuesta:
1/3+4/7 = 19/21
1/3+4/7 ; 1/3 = 7/21
= 7/21+4/7 ; 4/7 = 12/21
= 7/21+12/21
= (7+12)/21
= 19/21
9/10+3/4 = 33/20
9/10+3/4 ; 9/10 = 36/10
= 36/40+3/4 ; 3/4 = 30/40
= 36/40+30/40
= (36+30)/40
= 66/40
= (66÷2)/(40÷2)
= 33/20
3/7+1/2 = 13/14
3/7+1/2 ; 3/7 = 6/14
= 6/14+1/2 ; 1/2 = 7/14
= 6/14+7/14
= (6+7)/14
= 13/14
5/13+4/5 = 77/65
5/13+4/5 ; 5/13 = 25/65
= 25/65+4/5 ; 4/5 = 52/65
= 25/65+52/65
= (25+52)/65
= 77/65
2/3+5/6 = 3/2
2/3+5/6 ; 2/3 = 4/6
= 4/6+5/6
= (4+5)/6
= 9/6
= (9÷3)/(6÷3)
= 3/2
9/11+1/3 = 38/33
9/11+1/3 ; 9/11 = 27/33
= 27/33+1/3 ; 1/3 = 11/33
= 27/33+11/33
= (27+11)/33.
= 38/33
5/8+2/12 = 19/24
5/8+2/12 ; 5/8 = 15/24
= 15/24+2/12 ; 2/12 = 4/24
= 15/24+4/24
= (15+4)/24
= 19/24
3/4+7/15 = 73/60
3/4+7/15 ; 3/4 = 45/60
= 45/60+7/15 ; 7/15 = 28/60
= 45/60+28/60
= (45+28)/60
= 73/60
6/14+2/12 = 25/42
6/14+2/12 ; 6/14 = 36/84
= 36/84+2/12 ; 2/12 = 14/84
= 36/84+14/84
= (36+14)/84
= 50/84
= (50÷2)/(84÷2)
= 25/42
6/18+6/12 = 5/6
6/18+6/12 ; 6/18 = 12/36
= 12/36+6/12 ; 6/12 = 18/36
= 12/36+18/36
= (12+18)/36
= 30/36
= (30÷6)/(36÷6)
= 5/6
