Question

a student is solving 236 + 348 using partial sums. the students work is in the box below. 200 + 300 = 500 30 + 40 = 70 6 + 8 = 14 500 + 70 + 14 = 574 the student made a mistake. use place value language to describe the students error. correctly solve 236 + 348. use pictures, models, numbers, or words to support your answer.

Explanation:

Step1: Identify the error

The student added the digits correctly in each place - value column, but when combining the partial sums, there was an error in addition.

Step2: Correct partial - sum addition

We have hundreds: $200 + 300=500$, tens: $30 + 40 = 70$, and ones: $6+8 = 14$. When we combine these partial sums, we should think of $14$ as $1$ ten and $4$ ones. So we add the $1$ ten to the $70$ (the sum of the tens). So the sum is $500+(70 + 10)+4$.
$70+10=80$, then $500 + 80+4=584$.

Answer:

The student's error was not regrouping the 14 (1 ten and 4 ones) correctly when combining the partial sums. The correct sum of $236 + 348$ is $584$.