Letter
With letters you may calculate just as with numerals. Even a child understands that
1a + 1a = 2a
But there is of course more behind it.
Explanation
Often you work with letters because you do not know the exact value. You call such numbers x, y, z or p, q, r. For historical reasons, we use small letters. Usually, you have a combination of letters and numerals. That you see at
It consists of the numerals 1, 2 and 5 and the letters a en b. The digits form the decimal number 125, where the 1 represents 100, the 2 is for 20 and the 5 is for 5. The letters make the product a × b. If you write with brackets you get
A trickier number is
Here are the digits pulled apart, because it is easier to read. A different matter is
what you can better write as
Work as clear as possible.
Additional information
The French mathematician François Viète (1540 - 1603) introduced calculations with letters.