Usamos 8 CI's.

Available 74xx chips:

7400 - quad 2-input NAND gate
7402 - quad 2-input NOR gate
7404 - hex inverter gate
7408 - quad 2-input AND gate
7410 - triple 3-input NAND gate
7411 - triple 3-input AND gate
7420 - dual 4-input NAND gate
7421 - dual 4-input AND gate
7425 - dual 4-input NOR gate
7427 - triple 3-input NOR gate
7430 - single 8-input NAND gate
7432 - quad 2-input OR gate
7445 - BCD to decimal decoder
7448 - BCD to 7-segment decoder
7474 - dual D positive edge triggered flip-flop, asynchronous preset and clear
7485 - 4-bit magnitude comparator
7486 - quad 2-input XOR gate
74133 - single 13-input NAND gate
74138 - 3-to-8 line decoder/demultiplexer, inverting outputs
74139 - dual 2-to-4 line decoder/demultiplexer, inverting outputs
74147 - 10-line to 4-line priority encoder
74148 - 8-line to 3-line priority encoder
74150 - 16-line to 1-line data selector/multiplexer
74151 - 8-line to 1-line data selector/multiplexer
74152 - 8-line to 1-line data selector/multiplexer, inverting output
74153 - dual 4-line to 1-line data selector/multiplexer, non-inverting outputs
74154 - 4-to-16 line decoder/demultiplexer, inverting outputs
74157 - quad 2-line to 1-line data selector/multiplexer, non-inverting outputs
74158 - quad 2-line to 1-line data selector/multiplexer, inverting outputs
74174 - hex D flip-flop, common asynchronous clear
74175 - quad D edge-triggered flip-flop, complementary outputs and asynchronous clear
74185 - 6-bit binary to BCD converter
74260 - dual 5-input NOR gate
74283 - 4-bit binary full adder (has carry in function)
74374 - octal register