Month: April 2020

Factors and Multiples Chain

Today we worked on this lovely puzzle from Nrich.

Choose a starting number from a 1-100 square and cross it out.

Then choose a factor or multiple of that number.

Keep crossing out factors or multiples of the last number in the chain.

For example, Charlie started with 60, 30, 6, 96, 16, 32, 8, 56, 7, 21, 42,…

What’s the longest chain you can make?

There is an interactive place to play here

When you are using the activity make sure you only have a bracket at the start and the end … this attempt isn’t quite right:

There are two chains, rather than one continuous one.

But it can be fixed by swapping the 60,90,45 and 15 around:

Now it is a chain of 38 steps

Email Mrs Fleming on [email protected] if you can do better than 38 steps …

Sprouts

In honour of John H. Conway, today we present a game that he co-invented with Michael S. Paterson while they were both at Cambridge.

It is called Sprouts, and the rules are summarised by Nrich here.

Anyone can play, so find someone in your house and play a few games, then try and discover some of the maths behind it by working through this article.