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MathNet 2015-part-06 — 191 problems (EN–VI) Question 49

Math Olympiad Vault · MathNet 2015-part-06 — 191 problems (EN–VI)

Question 49

The tens digit of the product $1 \times 2 \times 3 \times \cdots \times 98 \times 99$ is
(A) 0 (B) 1 (C) 2 (D) 4 (E) 9