Черту дроби буду обозначать так: "/"
(1 - 7/15 + 0,4) : ( 8,3 + 4/19 - 15/38) = 266/2313
1. 1 - 7/15 = 15/15 - 7/15 = 8/15
2. 8/15 + 0,4 = 8/15 + 4/10 = 16/30 + 12/30 = 28/30 = 14/15
3. 8,3 + 4/19 = 83/10 + 4/19 = 1577/190 + 40/190 = 1617/190
4. 1617/190 - 15/38 = 1617/190 - 75/190 = 1542/190 = 771/95
5. 14/15 : 771/95 = 14/15 × 95/771 = 266/2313