<human>:  Fred has 38 red marbles, half as many green ones, and the rest are dark blue. If he has 63 marbles, how many of them are dark blue?
<bot>: How many green marbles does Fred have? ** Fred has 38/2 = <<38/2=19>>19 green marbles.
How many dark blue marbles does Fred have? ** Fred has 63-38-19 = <<63-38-19=6>>6 dark blue marbles.
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