Estimate the sum of 299 and 388
The Correct Answer and Explanation is:
Correct Answer:
The sum of 299 and 388 is 687.
Estimation and Explanation
Estimation is a useful mathematical strategy that helps us quickly predict the approximate result of a calculation without needing to compute the exact answer right away. It’s especially helpful when we want to make quick decisions or when precision isn’t necessary.
Let’s estimate the sum of 299 + 388:
To estimate, we round each number to the nearest hundred:
- 299 rounds to 300 (because it is only 1 less than 300),
- 388 rounds to 400 (because it is closer to 400 than to 300).
Now, we add the rounded numbers:
- 300 + 400 = 700
So, the estimated sum of 299 and 388 is approximately 700.
Now let’s find the exact sum:
- 299 + 388 = 687
We can check this by breaking it down:
- Add 300 and 388 first: 300 + 388 = 688
- But 299 is 1 less than 300, so subtract 1 from 688:
688 – 1 = 687
This confirms that the exact sum is 687.
Our estimate (700) is quite close to the actual answer (687). The difference is:
- 700 – 687 = 13
This small difference shows that estimation is a good way to get a quick idea of the total. Estimation doesn’t replace exact calculation, but it’s useful for checking reasonableness. If you added 299 and 388 and got something like 1200, you’d immediately know that’s too high—your estimate would tell you something is wrong.
In summary:
- Estimate: 700
- Exact Answer: 687
- Estimation helps you check your work and understand the scale of a problem.
