The high coincidence of two numbers is expressed as overlapping number. Iteration times, mathematical terms. Like 33, 222, 888, 888, numbers with the same digit are called overlapping numbers. The number of overlaps in mathematical terms is different from the number of overlaps. Basic concepts: number of iterations, mathematical terms. When the number on each digit is the same, it can be called an iteration. The number of overlaps in mathematical terms is different from the number of overlaps.