О тв е т:
По ш о в ое о бъ я сн е н и е :
2 1/6 + 2 5/12 = (2 + 2) + (2/12 + 5/12) = 4 7/12
9 3/8 + 7 5/6 = (9 + 7) + (9/24 + 20/24) = 16 + 29/24 = 17 5/24
5 1/10 + 8 3/8 = (5 + 8) + (4/40 + 15/40) = 13 19/40
6 2/15 + 42 18/25 = (6 + 42) + (10/75 + 54/75) = 48 64/75
5 3/18 + 18 1/27 = (5 + 18) + (9/54 + 2/54) = 23 11/54
9 3/20 + 7 4/15 = (9 + 7) + (9/60 + 16/60) = 16 25/60 = 16 5/12
2 19/44 + 5 52/66 = (2 + 5) + (57/132 + 104/132) = 7 161/132 = 8 29/132
38 21/26 + 14 34/39 = (38 + 14) + (63/78 + 68/78) = 52 131/68 = 53 63/68
6 11/12 + 3 15/16 = (6 + 3) + (44/48 + 45/48) = 9 89/48 = 10 41/48
х+12=50-20
х+12=30
х=30-12
х=18