Target 25

What a round is for

The interesting part is the path, not the moment you notice that the target is 25. Several pairings can be tried before one of them lands. The search is which numbers to pair and which operation to use.

Number-use constraints, the operations that will be allowed, and the scoring are still being designed. Nothing on this page is a final rulebook.

One worked path

Take 8, 3, 6 and 1, and the target 25. One valid path is (8 − 3) × (6 − 1). That is 5 × 5, which is 25.

The same four numbers can land on 25 another way: (6 × 3) + 8 − 1. Eighteen plus 8 is 26, and subtracting 1 leaves 25. Other paths may exist. Finding one does not exhaust the puzzle.

How the three modes would use it

In Training, a worked path can show why a solution holds. In Solo, you try the construction on your own. In Compete, the same kind of target can be given to more than one player. Those modes are planned. They are not open here.

Practising a puzzle makes you more fluent at that kind of puzzle. It does not establish a gain in general intelligence, or in performance outside the skill being practised.

A way through

• Keep the target in view before you spend a number.
• Look for a pair that makes a friendly factor of the target, such as 5 when the target is 25.
• If the first expression misses, change one operation rather than starting from a blank page.

Questions