It's just what people chose for the abbreviation for that word, like lb for the word pound. There is no l or b in pound.
But the logical answer is:
In fact, no. (once also written with a superscript o) is an abbreviation of Latin numero, the ablative of numerus 'number'; the ablative case is used for the meaning 'in number', which is how the abbreviation was first used.
Your question now will no doubt be "OK, then, why is 'no.' the abbreviation for 'numero'? Why not 'nu.'?" The answer to this is that abbreviations don't necessarily have the initial part of a word, especially if that's not the important part. So "Mister" is Mr., not Mi., and "verb" is vb. Knowing that numero has an -o ending is important, and that's why we have no.
The abbreviation no. is first found in English in the seventeenth century.
3.75*105
1.3*104
yes it should be
a number to the power of 2 is that number squared. It is abbreviated as number with 2 as the exponent, or the number with 2 superscript after it.
Numéro ( actually a word borrowed from Italian) is abbreviated No.
The atomic number of oxygen (abbreviated O) is 8.
The element, 'Oxygen' is abbreviated to 'O'.
The word care is sometimes abbreviated by the letter c. For example, the phrase "care of" can be abbreviated as c/o.
An abbreviated number is a number which has had significant figures removed in order to make calculations easier - a number which has been rounded to an appropriate degree.
with is abbreviated as "w/". You can also abbreviate without as "w/o".
Even though the word "number" has no "o" in it, the abbreviation is No. because it is based on the Latin word numero (which is also Spanish for number).
without is commonly abbreviated w/o
Jolly Old St. Nicholas.
1.3 * 101
Because it comes from the latin "numero"
3.75*105
1.3*104