Create the array of square roots of n for n=1,2,...,9

a1=Table[ Sqrt[n], {n,1,9} ]		exact
a1=Table[ N[Sqrt[n]], {n,1,9} ]		numerical

Create an array of 15 random real values uniformly distributed between 0 and 10

a2 = Table[10Random[],{15}]

Create a 5×5 array of integer chosen randomly between 1 and 100

a3 = Table[Random[Integer,{1,100}],{5},{5}]

Create an array x=(2, 2.3, 2.6, ..., 4.7, 5)
and then plot   sqrt(x) vs. x --
as a line plot, and then as a point plot


x = Table[ w, {w, 2.0, 5.0, 0.3} ]

ListPlot[Transpose[{x,Sqrt[x]}], PlotJoined->True]

ListPlot[Transpose[{x,Sqrt[x]}]]

Define the following vectors of 9 elements each:
u = (7, 4, 9.9, 0, 4, 3, 6, 2.1, 1.9)
v = (0, 0, 0, 0, 0, 0, 0, 0, 0)
w = (1.1, 1.2, 1.3, ..., 1.9)


u = {7,4,9.9,0,4,3,6,2.1,1.9}
v = Table[0,{9}]
w = Table[0.1 n, {n,11,19}]

Add two vectors (each of 7 elements), then plot the values of the result:

u = (3,0,1,4,2,6,4)
v = (1,2,3,4,5,6,7)
plot w = u + v


u = {3,0,1,4,2,6,4}
v = Range[1,7]
w = u+v;
ListPlot[w]