basic adder problem

Discussion in 'Homework Help' started by paksee, Mar 4, 2012.

  1. paksee

    Thread Starter New Member

    Mar 4, 2012
    Design a circuit that adds together 4X and 8X to give 12X, where X is X2X1X0, and gives a 7-*‐bit sum S6S5S4S3S2S1S0. This can be done using 1 full adder and 2 half adders, no additional gates are required.

    all I know is adding 2 bits with one half adder and use bunch of full adder to get a n bit sum...

    I have no idea what to do on this..

    please help