Выполните сложение: а)3 4/5+1 4/5 б)1 4/9+7 7/18 в)8 4/5+2 1/3 г)12 5/6+4/15 д)7/20+2 7/10 е)8 3/7+1 9/14

а) 3 4/5 + 1 4/5 = (3 + 1) + (4/5 + 4/5) = 4 + 8/5 = 4 + 1 3/5 = 5 3/5.

б) 1 4/9 + 7 7/18 = 13/9 + 133/18 = (13 * 2) / (9 * 2) + 133/18 = 26/18 + 133/18 = (26 + 133) / 18 = 159/18 = 8 15/18 = 8 5/6. 

в) 8 4/5 + 2 1/3 = 44/5 + 7/3 = (44 * 3) / (5 * 3) + (7 * 5) / (3 * 5) = 132/15 + 35/15 = (132 + 35) / 15 = 167/15 = 11 2/15. 

г) 12 5/6 + 4/15 =77/6 + 4/15 = (77 * 5) / (6 * 5) + (4 * 2) / (15 * 2) = 385/30 + 8/30 = 393/30 = 13 1/30.

д) 7/20 + 2 7/10 = 7/20 + 27/10 = 7/20 + 54/20 = 61/20 = 3 1/20;   

е) 8 3/7 + 1 9/14 = 59/7 + 23/14 = 118/14 + 23/14 = 142/14 = 10 2/14 = 10 1/7.