# Your Solutions - Stage 4 & 5

### Tens

##### Stage: 5 Challenge Level:

When is $7^n + 3^n$ a multiple of 10? Can you prove the result by two different methods?

### Giants

##### Stage: 5 Challenge Level:

Which is the bigger, 9^10 or 10^9 ? Which is the bigger, 99^100 or 100^99 ?

### Rhombuses from Diagonals

##### Stage: 3 and 4

Take a look at the video showing rhombuses and their diagonals...

### Getting Round the City

##### Stage: 3 and 4

In a city with a grid system of roads, how do you get from A to B?