Library / /114 of 175

, 2022

Number theory Difficulty 2.0 Junior Find the answer United Kingdom

Nine of the numbers $1, 2, 3, 4, 5, 6, 7, 8, 9, 10$ are to be put in two groups so that the sum of the numbers in each group is a multiple of four. What is the largest number that could be left out?

(A) $3$ (B) $4$ (C) $5$ (D) $6$ (E) $7$

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.