a <- sqrt (25)
b <- a*a
?sqrt

example (sqrt)

a <- 5*5
d <- "Dobry den"
class (d)
class (a)
a + d

e <- "25"
class (e)
a + e


A <- seq (from = 1, to = 30)
length (A)
A + a
class (A)
B <- c("Dobry den", "jak se mate", "date si", "pivo")
B
length (B)
C <- c (A, B)
C

M <- matrix (data = A, nrow = 6, ncol = 5, byrow = TRUE)
M

M [4,4]
M [2, 5]
M [2, ]
M [, 5]
dim (M)