1. Using Positive and Negative Numbers in Context
Projector Resources

2. You may use your temperature scale throughout this task to assist you.

3. Contextual Information
Water boils at 100⁰C. (212⁰F)
Water freezes at 0⁰C. (32⁰F)
An average summer day temperature is 30⁰. (86⁰F)
A cold winter day (in Los Angeles) is 15⁰C. (59⁰F)

4. Put these temperatures in order from coldest to hottest.
London +13⁰C
Vancouver -11⁰C
Paris +20⁰C
Beijing -5⁰C

5. If I fly from London to Beijing, does the temperature rise or fall?
Temperature Changes
London
+13°C
Beijing
−5°C
If I fly from London to Beijing, does the temperature rise or fall?
What is the change in temperature?
How do you know?

6. Temperature Changes
Paris
+22°C
Vancouver
−11°C
If I fly from Vancouver to Paris, does the temperature rise or fall? What is the change in temperature? How do you know?

7. Temperature Changes London +13°C Beijing −5°C Paris +22°C Vancouver
The temperature change is +24⁰C. What was my journey?
The temperature change is -6⁰C. What was my journey?
Cairo is 30⁰C warmer than Beijing. What is the temperature in Cairo?

8. Instructions for Working Together
Take turns to place cards.
When it is your turn, connect two City Temperature cards using a Changes in Temperature arrow card.
Figure out any missing temperatures.
Give reasons explaining your calculations.
If others in your group disagree, they should explain why. Then figure out the answer together.
When you have reached an agreement, write your solution in the box on the card.
Ignore the dashed lines on the cards, for now. We will be using them later.

9. More Temperature Changes
London
+8°C
+7°C
Madrid
_ _ _ _ _ _ _ _ _ _ _
What is the temperature in Madrid?
What calculation gives this answer?

10. More Temperature Changes
Berlin
_ _ _ _ _ _ _ _ _ _ _
Tromso
−7°C
What is the temperature in Berlin?
What calculation gives this answer?

11. More Temperature Changes
Tromso
−7°C
London
+8°C
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
What is the temperature change when you fly from Tromso to London?
What calculation gives this answer?

12. What is a general method used to figure out starting temperature?
What is a general method used to figure out a missing final temperature?
Starting Temperature + Change = Final Temperature.
What is a general method used to figure out starting temperature?
Final Temperature – Change = Starting Temperature
What is a general method used to figure out temperature change?
Final Temperature – Starting Temperature = Change

13. Writing Calculations
For each of the temperatures you have already written in the boxes, write a calculation on the dashed lines. When you have completed your posters, you may begin your homework.