Since I needed some extra practice sheets I created a packet and also a video that I posted to YouTube. In both of these resource I use a matching and circling strategy. I like having my students do this. They match the items in each category and then circle the extra. I found that this is a good strategy for helping students understand what I mean when I was ask for how many more or how many fewer. They can see that I am really asking for the difference between the two. For some reason this concept is really hard for them. They can tell that one category has more or less than the other, but they have a difficult time with the idea of comparing the two in order to answer the question of how many more or how many fewer.
I think that students really begin to understand this as they continue to develop their number sense, so long term it probably isn't a concern, but since my students need to have this for their unit test I wanted to give them a helping hand and additional practice.
Besides using the practice pages and the video I also used manipulative in order for students to see how the items in each category could be matched. You can see my blog on Creating Story Problems for more information on how I did this.
Here are the links to the resources that I have talked about in case you are interested.
Using Data to Tell How Many More or Less in a Category - Practice pages
Using Data YouTube Video
Creating Story Word Problems