Question

What is the nearest 100 of 829

Answer 1

8 is the hundreds place
look at the next smallest place
the tens place

if it is less than 5, round down (leave the hundreds as is and put zeros after it to replace the other digits)

if it is equal to or greater than 0, round up, add 1 to the hundreds


so
829
2<5 so round down
800 is rounded to nearest hundred