x <- "hello world!"

y <- "5"
z <- "3"

y+z

w <- paste(y,z)
w

nchar(x)
nchar(w)

date <- "2019-05-23"

substring(date,1,4)

substring(date,5,7)

is.character("5")

is.character(5)

number <- "5"
is.character(number)
number <- as.numeric(number)
is.character(number)