Create the combinational circuit for the following problems. Show the complete truth table and the propositional expression for each of its output. Simulate using a circuit simulator using switches as inputs and LED as output indicators. Use only 2 input logic gates in the design. Then provide a screenshot of 2 different input values with its output.

1. Design a 4 by 1 multiplexer allowing 4 inputs and 1 output. Label the inputs as ABCD and the output X.

2. Design a 2 bit subtractor meaning a 2 bit subtracted to another 2 bit. The 2 bit minued are labeled AB (A = MSB, B = LSB) and the 2 bit subtrahend are labeled XY (X = MSB, Y = LSB) and the 3 bit difference is labeled as PQR (P = MSB, R = LSB). Negative outcomes must be expressed in 1s complement (i.e. 0 1 = -1) decimal 1 = 001 (binary), -1 = 110 (1s complement)