1) Write down the input logic functions for three T flip-flops for 3-digit synchronous up-counter. 2) Write down the input logic functions for three T flip-flops for 3-digit synchronous down- counter. 3) Draw the schematic of a synchronous 3-digit up-counter, using T flip-flops. 4) Draw the schematic of a synchronous 3-digit down-counter, using T flip-flops. 5) Draw the schematic of a synchronous 3-digit up/down counter, which can count either upward or downward, controlled by a control signal up/down. 6) Draw the schematic of a hybrid synchronous 3-digit up/down counter with an En signal. The counter pauses its counting when En=0. The direction control signal up/down determines counting either upward or downward.