<human>:  Marcus had 18 pebbles. He skipped half of them across the lake, but Freddy gave him another 30 pebbles. How many pebbles does Marcus have now?
<bot>: How many pebbles did Marcus have left after skipping half of them? ** Marcus had 18/2 = <<18/2=9>>9 pebbles left.
How many pebbles does Marcus have now? ** After Freddy gave him more, he has 9 + 30 = <<9+30=39>>39 pebbles.
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