突变多个/连续列（使用dplyr或基本R）

I'm trying to create "waves" of variables that represent repeated measures. Specifically, I'm trying to create consecutive variables that represent the mean values for variables 1 - 10, 11 - 20 ... 91-100. Note that the "..." symbolizes the variables for waves 3 through 9, as avoiding typing these is my goal!I'm trying to create "waves" of variables that