x=c(7, 7,3,4,5,6,6,5,4,7)
table(x)#output 1st row x value 2nd row frequency
#if want table in vertical then 
transform(table(x)) #output 1st column serial no 2nd x value 3rd frequency


x=c(20,25, 30,35,40,45)
f=c(5, 3,11,2,9,15)
data.frame(x,f)#no name to columns
#if want to give name to columns then 
data.frame("age"=x,"nos of students"=f)#whatever name you given to variable use that if x then 'age'='x' if f then "nos of students"=f (not y)