### Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

### Tea Cups

Place the 16 different combinations of cup/saucer in this 4 by 4 arrangement so that no row or column contains more than one cup or saucer of the same colour.

### Counting on Letters

The letters of the word ABACUS have been arranged in the shape of a triangle. How many different ways can you find to read the word ABACUS from this triangular pattern?

# Rectangle Outline Sudoku

##### Stage: 3 and 4 Challenge Level:

Invented by Henry Kwok

### Rules of Rectangle Outline Sudoku

This Sudoku variant has two additional rules.

As usual, the object of the puzzle is to fill in the whole 9x9 grid with numbers 1 through 9 so that each row, each column and each box must contain all the nine different numbers 1 to 9 irrespective of order.

The two additional rules of the variant are as follows:
1. Each of the two main diagonals of the puzzle must have the numbers 1 to 9.

2. Within the 9x9 pattern there is a highlighted "rectangle" with its width four and length six cells respectively. Each width of the "rectangle" outline must contain all the four numbers 1 to 4. Similarly, each length of the "rectangle" must contain all the six numbers 1 to 6.