Identical squares of side one unit contain some circles shaded blue. In which of the four examples is the shaded area greatest?

There are six numbers written in five different scripts. Can you sort out which is which?

Charlie and Abi put a counter on 42. They wondered if they could visit all the other numbers on their 1-100 board, moving the counter using just these two operations: x2 and -5. What do you think?

Many numbers can be expressed as the difference of two perfect squares. What do you notice about the numbers you CANNOT make?

In 15 years' time my age will be the square of my age 15 years ago. Can you work out my age, and when I had other special birthdays?

What is the largest number which, when divided into these five numbers in turn, leaves the same remainder each time?

Take any four digit number. Move the first digit to the end and move the rest along. Now add your two numbers. Did you get a multiple of 11?

In this problem we are faced with an apparently easy area problem, but it has gone horribly wrong! What happened?

You are only given the three midpoints of the sides of a triangle. How can you construct the original triangle?