Doubt Regarding SPOJ

While going through the tags available on SPOJ, like dynamic programming and binary search, I saw a number written in parentheses beside the tag name, for e.g. “#dynamic-programming (318)” so I thought that there will be 318 problems available under the DP category but when I clicked on that tag the number of problems was far less than 318. So what does that number indicate? If it does indicate the number of problems then where can I find those hidden problems?