I need 15 flip flops to divide the clock crystal frequency to make it a 1 and then it will go to the input of the first decade counter which will count up to 9 and it will reset itself after 9 and when it is resetting itself that input will go to next counter of the minutes part which will count up to 6 and that will be the input for the next counter which is the first one in the hour part this counter will count up to 3 and resets itself at 4 which will become the input for the next and last counter which count up to 2 as this circuit is for the 24 hour clock.
