The Two Jugs
Measure exactly — with no markings
You have a 5-litre jug and a 3-litre jug and a tap. Neither jug has markings. How do you measure out exactly 4 litres?
Logic Puzzle
The River Crossing
A farmer must take a goat, a wolf and a cabbage across a river. The boat holds the farmer and only one other thing. Left alone, the wolf will eat the goat, and the goat will eat the cabbage. How does everything get across safely?
PlanningLogicAges 9–11 · 12+Sample content
Getting The River Crossing ready…
About this game
How to play
- Tap something on the farmer's side to put it in the boat (or leave the boat empty).
- Press 'Row across'. The farmer always rows the boat.
- Never leave the wolf alone with the goat, or the goat alone with the cabbage.
Three levels
- Easy: The farmer warns you before anything gets eaten.
- Medium: The classic puzzle: one careless trip and it's over.
- Hard: Get everyone across in 7 crossings or fewer — the best possible.
What this teaches
The step most people never think of is going backwards. Many problems only open up once you allow a move that seems to undo progress.
Keep playing
More brain games
Alive Without Breath
…and a whole box of riddles to unlock
I am alive without breath and as cold as death. I am never thirsty, though I always drink. What am I?
Word Ladder: COLD to WARM
Change one letter at a time
Change COLD into WARM one letter at a time. Every step in between must be a real English word. Four steps will do it.