5th Grade: Reasoning Problem:Released Item 2016 #23

Last updated over 3 years ago
2 questions
Required
1

A student solves this subtraction problem:



This is the reasoning the student used.
*You cannot take 9 ones away from 3 ones, so you need to get more ones.
*You cannot take any ones from 0 tens, so you skip to the hundreds. That makes 3 hundreds and 13 ones.
*You subtract 9 ones from 13 ones to get 4 tens.
*You subtract 0 tens from 0 tens to get 0 tens.
*You subtract 2 hundreds from 3 hundreds to get 1 hundred.
*You subtract 3 thousands from 6 thousands to get 3 thousands.

Part A:

Explain what is correct about the reasoning the student used to subtract the numbers.

3

A student solves this subtraction problem:



This is the reasoning the student used.
*You cannot take 9 ones away from 3 ones, so you need to get more ones.
*You cannot take any ones from 0 tens, so you skip to the hundreds. That makes 3 hundreds and 13 ones.
*You subtract 9 ones from 13 ones to get 4 tens.
*You subtract 0 tens from 0 tens to get 0 tens.
*You subtract 2 hundreds from 3 hundreds to get 1 hundred.
*You subtract 3 thousands from 6 thousands to get 3 thousands.

Part B:

Explain the error in the reasoning the student used to subtract the numbers. Then explain how to correct the error. Include the correct difference in your explanation.