Maths Olympiad Prep

Library / /11 of 146

, 2016

Number theory Difficulty 1.0 Junior Find the answer United Kingdom

How many times does the digit 9 appear in the answer to 987654321×9987654321 \times 9?

(A) 00 (B) 11 (C) 55 (D) 88 (E) 99

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.