Library / /93 of 165

, 2015

Number theory Difficulty 2.0 Junior Find the answer United Kingdom

How many two-digit squares differ by 1 from a multiple of 10?

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

Want a route through all this instead of an archive? The track puts 2,604 problems in a working order, from Junior Challenge level to the IMO shortlist.

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.