Using Addition
and Subtraction
Performance Task Objectives
Estimate sums and differences of 3digit to 6digit numbers
Add and subtract up to a 5digit number
Sunshine State
Standards
MA.3.A.6.1
Materials
Student recording sheet
Paper and pencil
Student arrangement
Individual
Task
Present the problem on the student Recording Sheet to your students.
Performance
Criteria
Does the student understand how to use estimation, addition, and subtraction
in drawing conclusions about the lengths of the rivers?
Do the student’s examples show a correct estimated sum and difference,
and a correct exact sum and difference?
Can the student explain how he or she found each sum or difference?
Directions
The table below shows the lengths of five of the longest rivers in North
America. Use the table to complete the following 5 tasks.
RIVER 
LENGTH (km) 
Arkansas 
2,353 
Mackenzie 
4,250 
Mississippi 
3,774 
Missouri 
3,734 
Rio Grande 
3,065 
 What is an estimated
sum of the lengths of the Arkansas and the Mississippi Rivers? Show
your work.
 What is the exact sum
of the lengths of these two rivers? Show your work.
 What is an estimated
difference in the lengths of the Rio Grande and the Mackenzie Rivers?
Show your work.
 What is the exact difference
in the lengths of these two rivers? Show your work.
 Write an explanation
of how you found the estimated sum or difference.
