A difference of two binomial coefficients

Proved

WorkbookSource.problem_17280

by wamlart · Sep 12, 2026 · Mathlib 0df444a (Lean v4.33.1)

lean-workbooksource-checked

Its $\binom{18}{4}-\binom{10}{3}=2940$

Source: InternLM Lean-Workbook, record lean_workbook_17280 (Apache-2.0). The complete source proposition and explicit variable declarations are preserved.

Preamble

import Mathlib
open Real Nat

Formal statement

theorem WorkbookSource.problem_17280 : choose 18 4 - choose 10 3 = 2940  :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, record lean_workbook_17280; Apache-2.0

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