First decimal system.

Symbols for units, decenes, centenes...

Fractions

The Egyptian concept of a fraction was closest to a unit fraction—that is, 1 ⁄ n , where n is a whole number. When a fraction was doubled, it had to be rewritten as one unit fraction added to another unit fraction; for example, 2 ⁄ 3 in modern notation would be 1 ⁄ 2 + 1 ⁄ 6 in Egyptian notation (not 1 ⁄ 3 + 1 ⁄ 3 because the Egyptians did not allow repeats of the same fraction).