When transmitting a mandatory directive, how must numbers be stated? What numbers are not required to be stated this way?

• A. Spoken by digit; Exact multiples of hundreds and thousands
• B. Spoken by words; No exceptions
• C. Written numerals; Decimal numbers only
• D. Spoken by digit; Exact multiples of hundreds and thousands

Answer: (D)

Numbers transmitted for a mandatory directive should be spoken digit by digit to avoid mishearing on the radio. The standard allows using the whole number form for round values that are exact multiples of hundreds or thousands, since those are quick, unambiguous, and don’t require reading every digit. So the best approach is to speak numbers by digits in general, with the exception that exact multiples of hundreds and thousands can be stated as a whole number. This aligns with clear radiotelephony practice.