Exploring and noticing

This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?

Can all unit fractions be written as the sum of two unit fractions?

Investigate what happens to the equation of different lines when you translate them. Try to predict what will happen. Explain your findings.

I've made some cubes and some cubes with holes in. This challenge invites you to explore the difference in the number of small cubes I've used. Can you see any patterns?

Investigate what happens to the equations of different lines when you reflect them in one of the axes. Try to predict what will happen. Explain your findings.

In this twist on the well-known Countdown numbers game, use your knowledge of Powers and Roots to make a target.

How many pairs of numbers can you find that add up to a multiple of 11? Do you notice anything interesting about your results?

You have a set of the digits from 0 to 9. Can you arrange these in the five boxes to make two-digit numbers as close to the targets as possible?

You have two sets of the digits 0-9. Can you arrange these in the five boxes to make four-digit numbers as close to the target numbers as possible?

Can you find a reliable strategy for choosing coordinates that will locate the treasure in the minimum number of guesses?