# Can somebody explain to me Cantor's diagonalization argument? [duplicate]

"The real numbers between 0 and 1 can be listed in some order, say, $r_1, r_2, r_3, ...$Let the decimal representation of these real numbers be
$r_1 = 0.d_{11}$$d_{12}$$d_{13}$$d_{14}... r_2 = 0.d_{21}$$d_{22}$$d_{23}$$d_{24}$... $r_3 = 0.d_{31}$$d_{32}$$d_{33}$$d_{34}... r_4 = 0.d_{41}$$d_{42}$$d_{43}$$d_{44}$...