Question

What's round the number to the nearest 100000

Answer 1

That would be rounding the number to the nearest hundred-thousand. 

example: 1,462,924 rounded to the nearest hundred-thousand would be 1,500,000

Answer 2

For example; if you have the number  123456, you would round it down to 100000 because the number following the first one is lower than five.
Hope this helps! :3