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I sent you 2 SBD and got 2.27 SBD board.
70% of them will be distributed to me, and 30% will be distributed to you.
My share is 2.27 * 70% = 1.589 SBD
1.589 - 2 SBD = - 0.411, because I lost the 0.411 SBD.
If this happens, who will send you a 2 SBD and get a ride?