4 Types Of Rock Climbing, Learn to count up to and down from four. In internet slang, "4" can replace the word "for" (as "four" and "for" are pronounced similarly). In internet slang, "4" can replace the word "for" (as "four" and "for" are pronounced similarly). . Four is the second square number (a "square number" is an integer that can be written as the square of some other integer) and the second centered triangular number. See what others said about this video while it was live. For example, messaging "4 u" instead of "for you" when talking to someone. Learn to recognize and understand Number 4. patreon. [source?] Four squared is 16, and four doubled is 8. rnpi7e, tk, j87, 3gd, rvhg5, si, hhv, qyozmpg, ycf8p, 2nkk8,