ccan arduino replace ttl ic's?

Hi. Im trying to make this digital clock http://electronics.howstuffworks.com/gadgets/clocks-watches/digital-clock.htm but radioshack didnt have the gates i needed (like nand,or,and,not,ect).i want to try to replace them with my arduino but Im new to electronic gates and arduino so i would have a really tough time figuring out how. Can anyone help?

Ah.

I cannot see why not. Use things like

inPinState = digitalRead(inputPin); outPinState = !inPinState; digitalwrite(outPin, outPinState);

you can use other operations as well. There is information on all the operations here:

http://arduino.cc/en/Reference/HomePage