# 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 ?

### Picturing the World

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

How can we make sense of national and global statistics involving very large numbers?

### Perception Versus Reality

##### Stage: 4 and 5 Challenge Level:

Infographics are a powerful way of communicating statistical information. Can you come up with your own?

### Estimating Time

##### Stage: 3, 4 and 5 Challenge Level:

How well can you estimate 10 seconds? Investigate with our timing tool.