Josh had w marbles in his collection. He lost x marbles and found y new ones. How many marbles does he have now?
Let's say that Josh had w marbles in his collection. He lost x marbles and found y new ones. How many marbles does he have now?

Josh had w marbles in his collection.

Josh lost x marbles.

Josh found y new marbles.

Josh has w - x + y marbles in his collection now.