Lory has 49 marbles. 
Solution:
Number of marbles Lory had before her birthday = 56 
Number of marbles Lory got on her birthday = 15 
On adding both the above values we get the total number of marbles.
Total number of marbles Lory has = 

Number of marbles Lory gave away = 22 
On subtracting the number of marbles given by Lory from the total number of marbles we get the number of marbles left with Lory 
i.e, Number of marbles left with lory = 

Thus, number of marbles left is 49.