Adding Negative Numbers
Lesson plan = 60 min activity
This has been developed for use on Sumdog (www.sumdog.com), a new
website offering high-quality, free mathematics games for students.
Classroom
resources
Objective
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Introduce addition with negative numbers
Structure
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60 min lesson
Offline classroom game followed by an online review
Resources
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Access to the Sumdog website
Student handout from our website:
http://www.sumdog.com/en/Adding_Negative_Numbers/
Plan
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Preparation (optional):
◦ Sign up for an account on Sumdog and create accounts for your students.
Activity (60 min):
◦ Introduce addition with negative numbers (15 min)
▪ Quickly review negative numbers.
▪ When you add two negative numbers, you are increasing the negativity.
▪ Show how the "minus" sign on a negative number is moveable. You can
move it up (addition with negative numbers) or bring it down (subtract a
positive number from a negative number).
◦ Classroom activity (20 min)
▪ Divide the class into two teams. Have each student write down a secret
negative number on a piece of paper.
▪ Each team sits in a circle. Pick one player as the starting point.
▪ On "Go", the students on either side of the starting player hold up their
numbers. The player must add the two numbers correctly AND restate the
problem as subtracting a positive number from a negative number.
▪ When they have finished, the next person goes. Teams race to be the first to
go completely around the circle.
◦ Play Sumdog games (25 min)
▪ Pass out the student handouts with instructions on using the site.
▪ They should work on the topics shown on the sheet while playing any of the
multiplayer games in Play Class mode.
Additional Resources
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Get additional resources to help you with this lesson at:
http://www.sumdog.com/en/Classroom_Resources/
Play Sumdog’s free mathematics games at http://www.sumdog.com/
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