Carl starts with 12 marbles to play with but loses 1/2, 12 / 2 = <<12/2=6>>6 marbles Carl didn't lose.
Carl takes out 10 more marbles, 6 + 10 = <<6+10=16>>16 marbles.
Then Carl's mother brings him 25 new marbles to add to the 16 he has out of his jar, 25 + 16 = <<25+16=41>>41 marbles that Carl is going to put in his jar after he plays his marbles game.
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