# Resources tagged with: Counting

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### There are 11 results

Broad Topics > The Number System and Place Value > Counting

### Ruler

##### Age 16 to 18 Challenge Level:

The interval 0 - 1 is marked into halves, quarters, eighths ... etc. Vertical lines are drawn at these points, heights depending on positions. What happens as this process goes on indefinitely?

### Binomial Coefficients

##### Age 14 to 18

An introduction to the binomial coefficient, and exploration of some of the formulae it satisfies.

### Links and Knots

##### Age 14 to 18

Some puzzles requiring no knowledge of knot theory, just a careful inspection of the patterns. A glimpse of the classification of knots, prime knots, crossing numbers and knot arithmetic.

### Adding with the Abacus

##### Age 5 to 16

Nowadays the calculator is very familiar to many of us. What did people do to save time working out more difficult problems before the calculator existed?

### Doodles

##### Age 14 to 16 Challenge Level:

Draw a 'doodle' - a closed intersecting curve drawn without taking pencil from paper. What can you prove about the intersections?

### Euler's Officers

##### Age 14 to 16 Challenge Level:

How many different ways can you arrange the officers in a square?

### Slippery Snail

##### Age 7 to 16 Challenge Level:

A game for two people, who take turns to move the counters. The player to remove the last counter from the board wins.

### Diagonal Sums Sudoku

##### Age 7 to 16 Challenge Level:

Solve this Sudoku puzzle whose clues are in the form of sums of the numbers which should appear in diagonal opposite cells.

### FEMTO

##### Age 14 to 16 Challenge Level:

A new card game for two players.

### Voting Paradox

##### Age 14 to 18 Challenge Level:

Some relationships are transitive, such as `if A>B and B>C then it follows that A>C', but some are not. In a voting system, if A beats B and B beats C should we expect A to beat C?

### FEMTO: Follow Up

##### Age 14 to 16 Challenge Level:

Follow-up to the February Game Rules of FEMTO.