SIMCC Games · Teacher guide
Last Stone
Take stones from the piles in turn; whoever takes the last one wins.
- Trains
- Strategy and planning ahead · Making things equal · Binary (Upper Division)
- Ages
- 8 and up
- In class
- Against the computer. One device each. Choose Lower Division: 2 piles of 2 to 7 stones. You go first, and every Lower start has a winning first move.
A ten-minute starter
- Show about 2 minDraw two piles, such as 3 and 5 stones. Players take turns to take any number of stones from one pile. Whoever takes the last stone wins. Play the class once.
- Play about 6 minStudents play the computer at Lower Division. After each game, read Why it went that way.
- Talk about 2 minAsk what first move people made. Lead the class to the plan: make the two piles equal, then copy the computer from the other pile.
Questions to ask the class
- The piles are 3 and 7, and it is your turn. What do you take?Listen for: 4 from the pile of 7, so both piles have 3.
- The piles are 4 and 4, and it is your turn. Can you be sure to win?Listen for: No. Whatever you take, the other player can make them equal again.
- Why does copying the other player work?Listen for: The piles stay equal after your turn, so you take the last stone.
A common mistake
Taking a whole pile, which leaves the other player one pile to take.
How to help: Ask them to compare the piles before each move. Hint (H) lifts a winning move when there is one, and says why.
Assign it
On the coach dashboard, choose your class under Cohorts. In Assign practice, pick Last Stone and the drill Last Stone, add a due date if you want one, then press Assign. Students find it on their Train page.
It opens against the computer. Ask students to start at Lower Division.
Wins against the computer show under By game, as each student's device reported them. Pass-and-play games do not show.