Lucy went to the grocery store. She bought 10 packs of cookie and 4 packs of cake. How many more packs of cookie did she buy over cake?
Lucy went to the grocery store. She bought 10 packs of cookie and 4 packs of cake. 

We want to know how many more packs of cookie she bought over cake. 

We can find this out by subtracting the number of packs of cake from the number of packs of cookie. 

10 - 4 = 6

Lucy bought 6 more packs of cookie than cake.