I am trying to make a decimal counter using LEDs that can either go up and down. Currently i am playing around with a simple up counter and another counter that can go left/right. I want to have two buttons one for increase and decrease but i'm not sure how to do this while keeping the previous LEDs on and without resetting them if no data is being sent through due to the clock pulse. I'd appreciate a point in the right direction because i have been at this for the past few days trying to learn the logic behind it but i need help.