R

You could use min-max (aka KNN) to normalize

#vacationdays
vacdays <- c(21,14,7)
#days since hired 
dayshired <- c(260,520,1040)

df <- data.frame( "VacationDays" = vacdays, "Working Days since hired" = dayshired, stringsAsFactors = FALSE)

#KNN
normalize <- function(x) {
    return ((x - min(x)) / (max(x) - min(x)))
  }
dfKNN <- as.data.frame(lapply(df, normalize))
# One could also use sequence such as df[1:2]
dfKNN <- as.data.frame(lapply(df[1:2], normalize))

I would prefer Z-Score as outliers get weighed better without drifting to mean
dfZScore <- as.data.frame( scale(df[1:2] ))