Paul got a box of 19 crayons for his birthday. During the school year he gave 8 crayons to his friends while he lost 39 crayons. How many more crayons did he lose than those he gave to his friends?
Paul got 19 crayons for his birthday. 
During the school year, he gave 8 crayons to his friends. 
That means he has 11 crayons left. 
During the school year, he lost 39 crayons. 
That means he has 50 crayons in total. 

Now we can solve this equation: 

19 + 39 = 50 

That means he lost more than those he gave to his friends by 21 crayons.