For federal purposes, the winnings of $900 are reported on the 1040, Line 21, and the losses up to the amount of winnings, $900, may be claimed on Schedule A under Other Miscellaneous Deductions; the remaining $40 may not be claimed.
half-sister - a sister who has only one parent in common with you. half sister, stepsister. sis, sister - a female person who has the same parents as another person; my sister married a musician.
Full siblings by definition have two biological parents in common (the mother and father), whereas half siblings have only one parent in common (either the mother or the father). It is impossible to determine which parent they share without further DNA samples.