Question

Darko found the sum of 324 and 57 to be 894. What error did he make?
(1 point)
• Darko did not regroup correctly after adding the ones digits.
• Darko did not align the digits by their place value when he set up the problem.
• Darko added 324 and 75 by mistake.
• Darko multiplied the numbers instead of adding them.

Answer 1

To determine the error Darko made, let's first correctly add 324 and 57.

1. **Align the numbers:**
```
324
+ 57
```

2. **Add the ones digits:**
- 4 (from 324) + 7 (from 57) = 11. Write down 1 and carry over 1.

3. **Add the tens digits:**
- 2 (from 324) + 5 (from 57) + 1 (carry) = 8.

4. **Add the hundreds digit:**
- 3 (from 324) + 0 = 3.

So, combining these results, we have:
```
324
+ 57
------
381
```

The correct sum of 324 and 57 is **381**. Darko found it to be **894**, which suggests a significant error.

From the options provided:
- **Darko did not regroup correctly after adding the ones digits.** - This could be true, but it alone doesn't explain the discrepancy.
- **Darko did not align the digits by their place value when he set up the problem.** - If he didn't align the digits, it's possible he added incorrectly.
- **Darko added 324 and 75 by mistake.** - This would result in 399 (not 894).
- **Darko multiplied the numbers instead of adding them.** - 324 multiplied by 57 is also not 894.

The most likely explanation is that **Darko did not align the digits by their place value when he set up the problem.**

So the best answer is:
- **Darko did not align the digits by their place value when he set up the problem.**