Vyashtisamashtih
Specific and general (vya · sh · ti · sa · mash · tih)
What it means
Break a hard problem into easy parts — and combine easy parts into a hard answer. Whichever direction makes the math simpler. This is the principle behind splitting a number for mental multiplication.
Worked example
Compute 47 × 8. Split 47 into 40 + 7. Now: 40 × 8 = 320, and 7 × 8 = 56. Add them: 376. The big problem became two small problems.