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UKMT Junior Kangaroo, 2019

Combinatorics Difficulty 2.0 Junior Find the answer United Kingdom

Riana has been asked to erase digits from the number 12 323 314 to obtain a number which reads the same from left to right as it does from right to left. What is the smallest number of digits Riana needs to erase?

(A) $1$ (B) $2$ (C) $3$ (D) $4$ (E) $5$

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