Darko's incorrect sum of 324 and 57 being 894 suggests he made an error in the addition process. The correct sum of 324 and 57 is 381 (324 + 57 = 381).
Let's analyze the provided options:
-
Darko did not align the digits by their place value when he set up the problem. - This could lead to an error but typically doesn't result in a sum that is this far off.
-
Darko added 324 and 75 by mistake. - This does not apply since 75 is not involved in the problem as stated.
-
Darko multiplied the numbers instead of adding them. - This would not yield a sum like 894 since the product of these two numbers (324 * 57) is much larger than 894.
-
Darko did not regroup correctly after adding the ones digits. - This is a likely error. When adding the ones digits, 4 + 7 = 11, which should cause a carry into the next column.
Given the options and the nature of the error, the most reasonable conclusion is:
Darko did not regroup correctly after adding the ones digits.