Abundant numbers are numbers whose factors add up to a higher number than the number itself. Confused? ...Good. Then sit back and listen.

Think of the number 12, and think of its factors. They are 1, 2, 3, 4 and 6. They add up to 16. 16 is higher than 12, so 12 is an abundant number.
Think of the number 24. 24's factors are 1, 2, 3, 4, 6, 8 and 12. They add up to 36. 36 is higher than 24, so 24 is abundant.

Got the picture? ...Good.

Now there are a couple of little tricks about abundant numbers that might impress your maths teacher even more. Ready? ...OK.

If a number's factors add up to the number itself, it is called a perfect number. Perfect numbers are very very rare indeed. There are only 3 below 500: 6, 28 and 496.

6's factors are 1, 2 and 3. Those three add up to make 6, so 6 is perfect, as is 28, with its factors being 1, 2, 4, 7 and 14. Don't ask me about 496 - work it out for yourself.

A weird number is an abundant number with a special little twist. If its factors add up to a number higher than the number it's abundant. If no combination of its factors add up to the number itself, it is also weird. Take a look at 12, 24 and 70:
You can get 12 from 6, 4 and 2, which are all factors of 12, so 12 is not weird.
You can get 24 from 12, 8 and 4, which are all factors of 24, so 24 is not weird. (But the TV show is.)
Try and get 70 out of 1, 2, 5, 7, 10, 14 and 35. I think you'll find it quite difficult. Therefore, 70 is weird.

Have a look for more abundant numbers - they're everywhere.