What is the smallest number with exactly 14 divisors?
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?
If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?
Sixteen unit squares are arranged to form a square array as shown in the diagram. What is the maximum number of diagonals that can be drawn in these unit squares so that no two diagonals share a common point (including endpoints)? 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.