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14 Divisors

What is the smallest number with exactly 14 divisors?

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Summing Consecutive Numbers

Many numbers can be expressed as the sum of two or more consecutive integers. For example, 15=7+8 and 10=1+2+3+4. Can you say which numbers can be expressed in this way?

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Dozens

Do you know a quick way to check if a number is a multiple of two? How about three, four or six?

Pentagon Ring

Stage: 3 Short Challenge Level: Challenge Level:1

Equal regular pentagons are placed together to form a ring as shown in the diagram, which shows the first three pentagons.

How many more pentagons are needed to complete the ring?

circle with chain of 3 pentagons.

 

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

This problem is taken from the UKMT Mathematical Challenges.

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