Unit 1 Learning Task: Hot Air Balloons
Name: ________________________
7.NS.1 Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers; represent
addition and subtraction on a horizontal or vertical number line diagram.
a Describe situations in which opposite quantities combine to make 0.
b Understand 𝑝 + 𝑞 as the number located a distance |𝑞| from 𝑝, in the positive or negative direction depending on whether 𝑞
is positive or negative. Show that a number and its opposite have a sum of 0 (additive inverses). Interpret sums of rational
numbers by describing real-world contexts.
c Understand subtraction of rational numbers as adding the additive inverse, 𝑝 − 𝑞 = 𝑝 = (−𝑞). Show that the distance
between two rational numbers on the number line is the absolute value of their difference, and apply this principle in realworld contexts.
d Apply properties of operations as strategies to add and subtract rational numbers.
In this task, hot air balloons will be used to deminstrate how to add and subtract integers. The vertical
position of the hot air balloon is determined by adding or removing a number of helium bags (or gas
bags), which represent positive integers, and sand bags, which represent negative integers.
1. Draw a vertical number line on ¼ inch graph paper. Use the lines of the graph paper and number the
vertical number line using three different colors: one for positive numbers, negative numbers, and zero.
2. On an index card, draw a hot air balloon and an arrow.
When using hot air balloons to add or subtract integers, there are several important things to remember.
 The first number indicates where the balloon starts.
 The sign tells you if you will be adding or subtracting from the balloon. An addition sign tells you
that you will be adding to the hot air balloon and a subtraction sign tells you that you will be
subtracting from the balloon
 The second number tells you what you will add or subtract from the balloon (positive-bags of gas,
or negative-bags of sand).
Use the number line and hot air balloon to model each situation.
What happens to the balloon when…
Add bags of gas
Balloon goes up
Add bags of sand
Balloon goes down
Subtract bags of gas
Balloon goes down
Subtract bags of sand
Balloon goes up
Mathematically
3 bags of gas (+3)
10 bags of gas (+10)
3 bags of sand (-3)
10 bags of sand (-10)
Subtract 3 bags of gas – (+3)
Subtract 10 bags of gas – (+10)
Subtract 3 bags of sand –(-3)
Subtract 10 bags of sand – (-10)
Use the number line and hot air balloon to model each problem and answer the questions that follow.
3. −𝟑 + 𝟔
A.
B.
C.
D.
Where does the balloon start? _____
Do you add or subtract from the balloon? _______________
What do you add or subtract from the balloon? _______________
Where does the balloon end up? _____
4. 𝟒 + (−𝟕)
A.
B.
C.
D.
Where does the balloon start? _____
Do you add or subtract from the balloon? _______________
What do you add or subtract from the balloon? _______________
Where does the balloon end up? _____
5. 𝟑 + (−𝟓)
A.
B.
C.
D.
Where does the balloon start? _____
Do you add or subtract from the balloon? _______________
What do you add or subtract from the balloon? _______________
Where does the balloon end up? _____
6. −𝟐 + (𝟗)
A.
B.
C.
D.
Where does the balloon start? _____
Do you add or subtract from the balloon? _______________
What do you add or subtract from the balloon? _______________
Where does the balloon end up? _____
7. What do you think happens to the balloon if you take away sand instead of adding sand?
8. What do you think happens to the balloon if you take away gas bags instead of adding gas bags?
9. 𝟔 − 𝟗
A.
B.
C.
D.
Where does the balloon start? _____
Do you add or subtract from the balloon? _______________
What do you add or subtract from the balloon? _______________
Where does the balloon end up? _____
10. −𝟑 − (−𝟗)
A.
B.
C.
D.
Where does the balloon start? _____
Do you add or subtract from the balloon? _______________
What do you add or subtract from the balloon? _______________
Where does the balloon end up? _____
11. −𝟏 − (−𝟑)
A.
B.
C.
D.
Where does the balloon start? _____
Do you add or subtract from the balloon? _______________
What do you add or subtract from the balloon? _______________
Where does the balloon end up? _____
12. −𝟔 − 𝟐
A.
B.
C.
D.
Where does the balloon start? _____
Do you add or subtract from the balloon? _______________
What do you add or subtract from the balloon? _______________
Where does the balloon end up? _____
Model the following with your balloon and number line. Describe what you did with the air balloon.
13. −𝟐 + (−𝟓)
15. −𝟐 + 𝟖
17. 𝟖 − (−𝟔)
19. 5 + 13
14. 𝟒 + (−𝟗)
16. 𝟓 − 𝟗
18. –7 – 4
20. – 𝟖 − (−𝟔)