Think of it as a doubling every day for a month.

On the 1st you have a penny.

On the 2nd you have 2 pennies.

On The 3rd you have 4 pennies

On the 4th you have 8 pennies.

On the 5th you have 16 pennies.

On the 6th you have 32 pennies.

On the 7th you have 64 pennies.

On the 8th you have 128 pennies.

On the 9th you have 256 pennies

and so on. By the end of the month, you have over 1 million dollars.