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Number theory Difficulty 1.0 Junior Find the answer United Kingdom

You are given the sequence of digits "0625", and can insert a decimal point at the beginning, at the end, or at any of the other three positions. Which of these numbers can you not make?

(A) $\frac{6}{25}$ (B) $\frac{5}{8}$ (C) $\frac{1}{16}$ (D) $\frac{25}{4}$ (E) $25^2$

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Source: UK Mathematics Trust, licensed © UK Mathematics Trust; past papers published free at ukmt.org.uk. Statement reproduced verbatim; metadata (topic, difficulty) added by this project. Solutions are the publisher's, linked not copied.