numbers ⫽ 0 ― 9999one-digit numbers (digits) ⫽ 0 ― 9two-digit numbers ⫽ 10 ― 99three-digit numbers ⫽ 100 ― 999three-digit numbers ⫽ 100 ― 999xxx1xx2xx3xx4xx5xx6xx7xx8xx9xxfour-digit numbers ⫽ 1000 ― 9999four-digit numbers ⫽ 1000 ― 9999x0x1x2x3x4x5x6x7x8x910xx11xx12xx13xx14xx15xx16xx17xx18xx19xx20xx21xx22xx23xx24xx25xx26xx27xx28xx29xx30xx31xx32xx33xx34xx35xx36xx37xx38xx39xx40xx41xx42xx43xx44xx45xx46xx47xx48xx49xx50xx51xx52xx53xx54xx55xx56xx57xx58xx59xx60xx61xx62xx63xx64xx65xx66xx67xx68xx69xx70xx71xx72xx73xx74xx75xx76xx77xx78xx79xx80xx81xx82xx83xx84xx85xx86xx87xx88xx89xx90xx91xx92xx93xx94xx95xx96xx97xx98xx99xxprime numbers ⫽ 2 ― 9973prime numbers ⫽ 2 ― 99730123456789xx1xx2xx3xx4xx5xx6xx7xx8xx9xx10xx11xx12xxcomposite numbers ⫽ 4 ― 9999composite numbers ⫽ 4 ― 99990123456789xx1xx2xx3xx4xx5xx6xx7xx8xx9xx10xx11xx12xx13xx14xx15xx16xx17xx18xx19xx20xx21xx22xx23xx24xx25xx26xx27xx28xx29xx30xx31xx32xx33xx34xx35xx36xx37xx38xx39xx40xx41xx42xx43xx44xx45xx46xx47xx48xx49xx50xx51xx52xx53xx54xx55xx56xx57xx58xx59xx60xx61xx62xx63xx64xx65xx66xx67xx68xx69xx70xx71xx72xx73xx74xx75xx76xx77xx78xx79xx80xx81xx82xx83xx84xx85xx86xx87xx
@ifckr.v.0.