Your stake is the amount placed on a bet. A total return includes the stake where the ticket defines it that way. Profit is the return minus the stake.
A simple example
A 10-unit cash stake at decimal odds of 2.50 has a 25-unit total return if it wins under those odds:
10 × 2.50 = 25 returned; 25 − 10 = 15 profit.
A losing 10-unit bet has a 10-unit loss. If a 10-unit stake is returned on a voided single, the net result is zero. These examples explain the arithmetic; your accepted ticket and market rules determine the actual settlement.
Cashout and combinations
An 8-unit total cashout on a 10-unit stake means a 2-unit loss, not an 8-unit profit. Check the confirmed cashout result rather than an earlier quote.
For a system bet, compare all returns with the sum of the combination stakes. One winning combination does not necessarily make the full ticket profitable.
Promotional free bets can have different stake-return terms. Read that offer rather than applying the cash-bet example automatically.
Use the ticket's original currency when checking the calculation. A changing fiat display or a later exchange rate should not be mistaken for a change to the accepted odds or settled return.