A. Unfortunately, there is no easy way to calculate e raised to some power 'n' like there is with p. At least, not one that I know of. Because of this, one can only memorize approximates to these powers.
B. Below are approximates of the powers of n, taken to the 8th power. There should be little need to memorize any more than this.
en and its approximate value
| e1 | 2.7 | e5 | 150 |
| e2 | 7.5 | e6 | 400 |
| e3 | 20 | e7 | 1100 |
| e4 | 55 | e8 | 3000 |
C. Here are some ways we can use these approximations in a question:
Ex [1] (5e)3 = __________.
a. Using the chart above, we can approximate this to be 53 x 20 or 125 x 20.
b. 125 x 20 = 2500.
c. The answer can be between 2386 and 2636.
Ex [2] 137e7 = __________.
a. Using the chart we can approximate this to be 137 x 1100.
b. 137 x 1100 = 150700.
c. The answer can be between 142727 and 157750.
D. This method of memorizing is not ideal, but it was the way I did them when I was taking the tests. If you have your own way, then by all means use it.
E. Also, note that these are already approximates. It would not be wise to approximate these approximates as you might get beyond the 5% window. These approximates, taken like they are, are guaranteed.