Question

The volume of a barrel of oil is calculated as 257,166 cm³. Round this figure to the nearest hundred thousand.

Answer 1

The hundred thousand digit is the 2 in 257,166. Because the ten thousands digit is 5, you round up to 300,000

Answer 2

we know that

To Round a number

a) Decide which is the last digit to keep  

b) Leave it the same if the next digit is less than $5$ (this is called rounding down)  

c) But increase it by  $1$ if the next digit is  $5$ or more (this is called rounding up)

In this problem we have

$257,166$

Round to the nearest $100,000$

We want to keep the digit $2$

The next digit is $5$ which is $5$ or more, so increase the digit $2$  by $1$

therefore

the answer is  

$300,000$