> airquality_C <- mutate(airquality, Temp_C = (Temp-32)*(5/9))
> head(airquality_C)
  Ozone Solar.R Wind Temp Month Day   Temp_C
1    41     190  7.4   67     5   1 19.44444
2    36     118  8.0   72     5   2 22.22222
3    12     149 12.6   74     5   3 23.33333
4    18     313 11.5   62     5   4 16.66667
5    NA      NA 14.3   56     5   5 13.33333
6    28      NA 14.9   66     5   6 18.88889