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?

Think of Two Numbers

Stage: 3 Challenge Level:

Here is an alternative and more unusual version of the "Think of a Number" game which you may have heard of before.

Think of two whole numbers under $10$.
Take one of them and add $1$.
Multiply by $5$.
Add $1$ again.
Double your answer.
Subtract $1$.
Add your second number.
Add $2$.
Double again.
Subtract $8$.
Halve this number and tell me your answer.

From your answer I can work out both your numbers very quickly. How?

Try with different numbers until you see how it works and then you'll be ready to amaze your friends!