its a programmable binary coded decimal up down counter. it is used in clocks . but you can use it for a varierty of other things. the basic ifunction is its four flipflops shifting 1's and zeros aka counting. you connect ce to ground enanling the clock. connect cp to a clock puls or oscilator dealy q0 -q3 are your outputs . when pl goes low it loads the bcd number you put into p0 -p3. if u/d is high it counts up if its low it counds down. rc and tc have to do with using the chip as a ripple counter. look up ripple counters i for get what the importance of that is exactly. most of what i remember from school revolves around the 74293 which is what i built digital clocks with. but i useal all of these chips at one point or another.