2 in Morse code

All ten digits are five elements long, and the first five count with dots. 2 sits between 1, .----, and 3, ...--: one more dot than 1 and one fewer dash. If you can hear where the short tones end, you can read every digit from 1 to 5.

At 18 words per minute 2 lasts 15 units, exactly one second: two dots of about 67 ms, three dashes of 200 ms and the short gaps between them.

8 is ---.., the elements of 2 played from the other end. Both have two dots and three dashes, both last one second, and only the order differs. Listen to how the character opens: short tones first mean 2, a long tone first means 8.

7, --..., is the other near miss: it is 2 with every dot turned into a dash and every dash into a dot. The Sound-alike drill plays pairs like these until they stop sounding alike.

International Morse has no percent signal. ITU-R M.1677-1 sends the sign as 0, the fraction bar and 0, and joins it to the number with a hyphen: "For 2%, transmit 2-0/0, and not 20/0." Without the hyphen the receiver could read twenty over zero.

Sent in full, 2-0/0 is ..--- -....- ----- -..-. -----, five characters with the hyphen and slash in the middle. The same rule joins a fraction to a whole number, as in 2-1/2.

In contest exchanges, where both stations expect figures, operators may send cut numbers: the dashes are trimmed to one and the dots kept. 2 becomes ..-, the letter U, and saves 8 of its 15 units.

Outside an exchange like that, send 2 in full. The numbers page lists the cut form of every digit.

• Tap it:

  two quick taps, then three long presses, about 1 second in all at 18 words per minute.

• Flash it:

  as light it takes longer, because the site flashes light at 7 words per minute or slower, so 2 takes about 2.6 seconds as a light signal.

• Write it:

  two periods and three hyphens with no spaces inside, then check it in the translator if you like.