Is there a term denoting the writing of words using numbers instead of letters?

Solution 1:

1337 speak: (also leet speak) Leet stands for Elite. Leetspeak is an alternative alphabet for English by replacing it with a number or combination of numbers.
'7H15 1S WR1773N 1N 1337 5P34K'

Solution 2:

From this web page comes the following:

1337 speak

Okay, 1337 is a good subject to talk about. The first thing I would like to clear up is that chatspeak and 1337 are NOT the same thing. Some lazy morons merge 1337 and chatspeak together, soon creating the popular belief that 1337 and chatspeak are the same thing.

Okay, so what /is/ 1337 in the first place? 1337 means Elite. The point of 1337 is to replace all the letters with symbols, and is quite fun to play with. 1337 was first created by some people would wanted to talk in a forum without any outsiders barging in. Some outsiders may have figured out the language and started using it as well. Eventually, 1337 became famous all over the internet. The original use of 1337 is hardly practiced any more, but it survives because many of peope use it for fun.

It takes a long time to translate between regular English and 1337 even if you know all 26 1337 secrets, unless you're very skilled at it.

Here are the 26 1337 [i.e., l-e-e-t] secrets. A = 4 B = |3 C = ( D = |) E = 3 F = |= G = 6 H = |-| I = | J = 9 K = |< L = 1 M = |v| N = |/| (It is backwards because the frontslash under the backspace key is famous for not showing up on many websites.) O = 0 (zero) P = |* Q = 0, R = |2 S = 5 T = 7 U = |_| V = |/ W = |/|/ X = >< (Is normal in words like |-|4x0|2) Y = `/ Z = 2

S0m3 p30ple 4r3 700 l4zy 70 wri73 7hin65 in fu11 1337, r3su17ing in a 53n73nc3 1ik3 7hi5.

If you wrote this sentence in 1337 speak, it would look like this: ||= `/0|| |/|/|2073 7|5 53|/|73|/|(3 ||/| 1337, |7 |/|/0||1|) 100|< 1||<3 7|-||5.

by Courage the cowardly dog April 07, 2006