Next, calculate the sum of the digits.

Note: The sum of the individual digits is usually compared with a previously computed value.

Strength is associated through the cross sum (the sum of the digits) with The Star.

The depreciation method can be straight-line, reducing balance, sum of the digits, economic, or indeed any other, so long as the periodic charge is fair.

Equivalently, the sum of the digits of a pernicious number, when represented in base 2, is a prime.

Ten was a sacred number, largely because it is the sum of the first four digits.

Let be the sum of the digits of .

The sum of the digits 0 to 9 is 45, passing the divisibility rule for both 3 and 9.

It is related through cross sums (the sum of the digits) with Key 14: Temperance.

A slightly more complex method is to take the weighted sum of the digits, modulo 10, with different weights for each number position.