Numbers are sometimes a problem for inexperienced dictators. Most “teen” numbers can easily be confused with “ty” (pronounced “tee’) numbers such as: 13/30, 14/40, 15/50/ 16/60, 17/70, 18/80. Dictating numbers properly and in the accepted manner is a good way to avoid any misunderstanding and is simple.
Here are some examples of how you should say numbers:
15 ………………… “Fifteen. That’s one, five.”
50 ………………… “Fifty. That’s five, zero.”
17 ………………… “Seventeen. That’s one, seven.”
When dictating file numbers, medical numbers, etc., Social Insurance or Social Security numbers, make sure you know the pace of the number. By this, I mean a number that is listed as “1234 567 899” should NOT be dictated as 123, pause, 4567, pause, 899. Just pausing between numbers, even if your pause is clear, as in “1234” (pause) “567” (pause) “899,” is not good enough, as the transcriptionist still may not know where to place the spaces between numbers. Rather, try to keep the pattern of the number as well as stating the separating spaces, by saying “1234, space. 567, space. 899.” Proper “number pace” is important to transcriptionists, as the number is more easily transcribed and is also more likely to be accurately transcribed. (Try this: sit at your computer and have someone tell you an unknown number of unknown length, without them stopping, while you type it exactly as it should be.)
If you are dictating a long number, keep the numbers in groups of three or four, for easier transcription. Very important also is the point that “0” (zero) is a number; “o” (oh) is a letter. The number “506” should be dictated as “five, zero, six,” not “five, oh, six.” This is of the utmost importance in file numbers that include letters of course, as the transcriptionist will consider all “o” sounds as the letter “o,” and will transcribe it accordingly.
Source: UK Typing