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### Number and algebra

### Geometry and measure

### Probability and statistics

### Working mathematically

### For younger learners

### Advanced mathematics

# See the Light

I've thought of a rule.

Numbers that obey my rule will light up the light.

Try entering some numbers.

Can you determine the rule?

*This activity is featured in the second half of Alan Parr's article Rocking Chairs, Railway Games and Rayboxes.*

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Age 7 to 14

Challenge Level

I've thought of a rule.

Numbers that obey my rule will light up the light.

Try entering some numbers.

Can you determine the rule?

Can you guess the colours of the 10 marbles in the bag? Can you develop an effective strategy for reaching 1000 points in the least number of rounds?

This problem offers you two ways to test reactions - use them to investigate your ideas about speeds of reaction.

We're excited about this new program for drawing beautiful mathematical designs. Can you work out how we made our first few pictures and, even better, share your most elegant solutions with us?