### 14 Divisors

What is the smallest number with exactly 14 divisors?

### 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?

### Dozens

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

# As Long as Possible

##### Stage: 3 Short Challenge Level:

The length of each side of a quadrilateral $ABCD$ is a whole number of centimetres. Given that $AB=4 \; \text{cm}$, $BC = 5 \; \text{cm}$ and $CD = 6 \; \text{cm}$, what is the maximum possible length of the fourth side $DA$?

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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