### N000ughty Thoughts

How many noughts are at the end of these giant numbers?

### Mod 3

Prove that if a^2+b^2 is a multiple of 3 then both a and b are multiples of 3.

### Euler's Officers

How many different ways can you arrange the officers in a square?

# More Mods

##### Age 14 to 16 Challenge Level:

What is the units digit for the number 123$^{456}$?