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?
Marcus had 18/2 = <<18/2=9>>9 pebbles left.
After Freddy gave him more, he has 9 + 30 = <<9+30=39>>39 pebbles.
#### 39