Design a combinational circuit that accepts a 3 bit number and generates a 6 bit binary number equal to the square of the input number?

Let the inputs be A2 A1 A0 & outputs be S5 S4 S3 S2 S1 S0.

Now, make a truth table as follows

A2 A1 A0 S5 S4 S3 S2 S1 S0

0 0 0 0 0 0 0 0 0

0 0 1 0 0 0 0 0 1

0 1 0 0 0 0 1 0 0

and so on.......

Finally we'll get

S0 = A0

S1 = 0

S2 = A1 A2(bar)

S3 = A0 [ A1 XOR A2]

S4 = A2 [A1(bar) + A0 ]

S5 = A1 A2