This is a simple digital counter of pulses with 7-segment LED displays. There may be any number of digits. I have chosen decimal counters 4026 (MH4026, HCF4026, CD4026, etc.). Their advantage is that you don't need binary decoders from BCD to 7-segment signal. Displays are common cathode, such DC56-11GWA. Resistors are not needed because the output of IO gives only a small current. Number of digits is arbitrary. Output: "10" from a lower digit IC is always connected to the input (clk) of higher digit IC. Impulses are fed to the input clk of IC of lowest digit. All ICs are reset by pressing button, which brings a positive level on the RESET input. Circuit voltage supplied should be about 4 to 7V. It can be stabilizated using for example 7805. The design is very simple, and therefore it would not make problems to beginners. Counter has a broad application, such as counting turns on winder, counting products, failures, error conditions and so on. It can also be used as a basis of GM counters with Geiger-Muller tube.
