Shortcut to find the reminder on dividing the number by 27 and 37

To find reminder on dividing the number by 27 and 37
Rules
1. Make triplets the given Number
2. To add all Triplets
3. If the addition value more than 999, proceed rule no.1
4. Finally to the result Divide 27 and 37 the reminder value is equal to the reminder of given number of dividing the number by 27 and 37.

Example:
Number = 25636921
Triplets = 25, 636, 921
Add Triplets = 25 + 636 + 921 = 1582

Again make triplet = 1, 582
Add triplet = 1 + 582 = 583

583 / 27 = 16
25636921 / 27 = 16

583 / 37 = 28
25636921 / 37 = 28