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### Number and algebra

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### Working mathematically

### For younger learners

### Advanced mathematics

# Working Systematically - Challenges

### Reach 100

### Sticky Numbers

### ACE, TWO, THREE...

### Two and Two

### Product Sudoku

### Pair Sums

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Once you are confident that you can work systematically, why not try some of these challenges?

Age 7 to 11

Challenge Level

Choose four different digits from 1-9 and put one in each box so that the resulting four two-digit numbers add to a total of 100.

Age 11 to 14

Challenge Level

Can you arrange the numbers 1 to 17 in a row so that each adjacent pair adds up to a square number?

Age 11 to 14

Challenge Level

Can you picture how to order the cards to reproduce Charlie's card trick for yourself?

Age 11 to 16

Challenge Level

How many solutions can you find to this sum? Each of the different letters stands for a different number.

Age 11 to 16

Challenge Level

The clues for this Sudoku are the product of the numbers in adjacent squares.

Age 11 to 14

Challenge Level

Five numbers added together in pairs produce: 0, 2, 4, 4, 6, 8, 9, 11, 13, 15 What are the five numbers?