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### Number and algebra

### Geometry and measure

### Probability and statistics

### Working mathematically

### For younger learners

### Advanced mathematics

# Your Number Was...

This problem follows on from Your Number Is...

Press the button in the interactivity below to investigate what this machine does:

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### Think of Two Numbers

### Special Numbers

### Your Number Is...

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Age 11 to 14

Challenge Level

This problem follows on from Your Number Is...

Press the button in the interactivity below to investigate what this machine does:

Try starting with other numbers - maybe decimals or negative numbers.

How is the machine working out your starting numbers?

Can you devise your own set of instructions so you can work out someone else's starting numbers in the same way?Think of two whole numbers under 10, and follow the steps. I can work out both your numbers very quickly. How?

My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?

Think of a number and follow the machine's instructions... I know what your number is! Can you explain how I know?