Question

Make an estimate for $279+473$ by rounding to the nearest hundred.

• A. $800$
• B. $600$
• C. $700$

Answer 1

The correct option is A $800$

We will start by rounding off the numbers to the nearest hundred, we need to look at tens place digit.

For $279$, its tens place digit i.e. 7 is above 5 so, we can round it up to 300.
From the number line also we can observe 279 is closer to 300, than 200.


Similarly for $473$, its tens place digit i.e. 7 is above 5 so, we can round it up to 500.
Similarly from the number line we can observe 473 is closer to 500 than 400.
Now if we add up our rounded up numbers, we get $300+500=800$.

Let's match with the original sum, $279+473=752$ which is very close to our estimate.