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

Josh had $x$ marbles in his collection. He lost $y$ marbles and found $z$ new ones. How many marbles does he have now?

$x = 19, y = 11, z = 5$

$x - y + z = 19 - 11 + 5 = 13$

Josh has 13 marbles now.