GridWits
Medium tier Technique 4 of 20 Used by Smart Hint

Combination Elimination

A digit that appears in none of this run's remaining sum combinations can be ruled out of every cell in it.

How it works

  1. 1Two cells sum to 7: the combinations are 1+6, 2+5, and 3+4.
  2. 2No combination contains a 7, 8, or 9 — whatever crossing runs might otherwise allow.
  3. 3Strike every digit that appears in none of the run's combinations.
7 3 4 7 4 5 8
  • Cells that establish the pattern
  • Digit ruled out
Next in the ladder Run Bounds →

Test one candidate against the smallest and largest distinct totals the other cells can still make. If the needed remainder lies outside those bounds, remove it.