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### For younger learners

# Surprise!

### Subtraction Surprise

### Angles Inside

### Legs Eleven

### Triangle in a Triangle

### Areas and Ratios

### Another Triangle in a Triangle

### Related

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Curiosity is triggered when something unexpected happens. These problems aim to draw students in by offering that element of surprise.

Age 7 to 14

Challenge Level

Try out some calculations. Are you surprised by the results?

Age 11 to 14

Challenge Level

Draw some angles inside a rectangle. What do you notice? Can you prove it?

Age 11 to 14

Challenge Level

Take any four digit number. Move the first digit to the end and move the rest along. Now add your two numbers. Did you get a multiple of 11?

Age 14 to 16

Challenge Level

Can you work out the fraction of the original triangle that is covered by the inner triangle?

Age 16 to 18

Challenge Level

Do you have enough information to work out the area of the shaded quadrilateral?

Age 16 to 18

Challenge Level

Can you work out the fraction of the original triangle that is covered by the green triangle?