Depending upon the phone, when you are in text entry mode, you can switch to all numbers, symbols or text. If you want to add a few numbers in the middle of a lot of text, you can hold the number down until a numeral appears. You can also use multiple tap on a key to go through the choices until the numeral appears. It usually comes after the three or four letters on the keys. In the case of the "1" key, there are several symbols and punctuation marks which appear before the numeral.
