You are given a math word problem and you are supposed to only use subtraction on the numbers embedded in the text to answer the following question and then only report the final numerical answer.
One example: Context: Sam is 6 feet tall and Alex is 5 feet tall 

 Question: By how many feet is Sam taller than Alex? 
Solution is here: 1
Explanation:  Sam's height - Alex's height = 6-5 = 1

Now, solve this: Context: Baker made 13 cakes. He sold 91 of them and bought 154 new cakes. 

 Question: How many more cakes did baker buy than those he sold?
Solution:
63