Brainsteem Mathematics Challenges - Coloured Numbers

The Question

Each number from the set {1,2,3,4,5,6,7,8,9} is coloured either red or blue according to the following rules:

i) The number 4 is red;
ii) If two numbers x, y have different colours and x + y < 9, then the number x + y is coloured blue;
iii) If two numbers x, y have different colours and x.y < 9, then the number x.y is coloured red

Find all possible colour arrangements.

This is at the level of a secondary national mathematics competition.

Try to share your method so as to help each other learn new techniques and strategies.

---

Come and check out Brainsteem challenges and other Mathematical posts currently live!

Brainsteem Compute #4 Prize Computational Maths Puzzle [Win 40% and 10% in SBD]

Brainsteem Compute #3 Prize Computational Maths Puzzle [Win 40% and 10% in SBD]

Brainsteem Mathematics Challenges - Upside Down Number

Brainsteem Mathematics Challenges - Digital Sum

Some non-mathematical posts:

Steemit, Neo and the Architect - the Solution to an Anomaly

Ideas for Future Rule Changes - Voting, Earnings, Maximum Social Benefits - a Discussion Document

---

Please upvote, resteem and follow @rycharde for more Brainsteems!

And don't forget to upvote each other's comments to bring cheer to the whole community!