In binary fission, one cell reproduces into 2 identical cells. This is a method of asexual reproduction commonly found in prokaryotes such as bacteria, and in some single-celled eukaryotes. During binary fission, the cell duplicates its contents, including its genetic material, and then divides into two equal-sized daughter cells, each with a complete copy of the original cell's DNA. The other numbers you've listed—3, 1, and 4—are not outcomes of binary fission.
