We require a mnemonic to remember e whenever we scribble math. To express e, remember to memorize a sentence to simplify this

e = 2.7182818284

Mnemonic Device:

2 = We
7 = require
1 = a
8 = mnemonic
2 = to
8 = remember
1 = e
8 = whenever
2 = we
8 = scribble
4 = math

Variation: To express e, remember to memorize a sentence to simplify this.

Explanation: The lengths of the words, in both sentences, constitute the number 2.7182818284 e. This number is the base for natural logarithms.