Round each to the place indicated.
1) 8,632,051 rounded to the nearest billion

1,000,000,000

Step-by-step explanation:

To round you have to look at the number to the right of what you're rounding to which in this case is the 8.  When rounding if the number is between 1 and 4 you round down and if the number is between 5 and 9 you round up.  Since it is 8 you round up and the nearest billion above the current number is 1 billion.

I hope this helps and please don't hesitate to ask if there is anything still unclear!