Josh had 19 marbles in his collection. He lost 11 marbles and found 5 new ones. How many marbles does he have now?
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Josh had 19 marbles. 

He lost 11 marbles. 

That means he has 19 - 11 = 8 marbles left. 

He found 5 new marbles. 

That means he has 8 + 5 = 13 marbles now.