Justin had 20 puzzles. He gave 1/2 of them to Jack. Connor gave Justin 4 puzzles. How many puzzles does Justin have now?
He now has 6 puzzles because he gave half of them to jack and half of 20 is 10.
And then he gave 4 puzzles to Justin so you subtract 10 - 4 and get 6
So your answer is 6!