Descending Anchor Heuristic
GMAT glossary · Playbook
Definition
Listing unique number combinations in strict descending order as anchors, then multiplying each working anchor by its shuffle factor.
Descending Anchor Heuristic in plain English
Use the Descending Anchor Heuristic when combinations of numbers must hit a sum, product, or average constraint. Clues include sum of three rolls is 14 or product of three cards is 60. List unique digit combinations in strict descending order (6-5-3). That list is your Anchor. When an anchor works, multiply by the shuffle factor 3! or (3!)/(2!). Random sequences duplicate permutations and miss cases; anchors inventory each multiset once, then permute. The descending order is a discipline that stops you from rediscovering 3-5-6 after you already counted 6-5-3. Micro-example: three dice sum to 14. Anchors include 6-5-3 and 6-4-4. For 6-5-3 multiply by 3! = 6; for 6-4-4 multiply by (3!)/(2!) = 3. Add the branches for the full count.
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