Example 1
Find the value of -7 + (-5).
- Both numbers are negative.
- Add their absolute values: 7 + 5 = 12.
- Keep the negative sign: -12.
Answer: -12
📗 Class 7 maths · session 1 of 12 · 60 minutes · free
Welcome aboard, Hero! Captain Calc needs your math superpowers to defeat negative confusion and master integers.
🤖 Written with Google's Gemini AI. A second AI solved all 55 questions without seeing the answers, and both agree. One of our teachers has not read it yet, so if something looks wrong, please tell us.
A complete lesson · 60 minutes
Open this page with your learner and work down it, or press Teach this lesson to go through it one step at a time on a big screen. Every section has something to do.
Class 7 · CBSE, ICSE and state boards
Warm-up · think first
-12 degrees. Dropping 3 degrees 4 times means 4 × (-3) = -12.
Teacher tip: Ask students if a negative number makes sense for temperatures below zero.
🎮 Warm-up games · 5 quick games
Six minutes with Captain Calc. Vote, say why, then show the answer.
Part 1 of 4 · learn, see, practise
Integers include zero, positive numbers, and negative numbers.
When adding integers with the same sign, add their values and keep the common sign.
When adding integers with different signs, subtract the smaller value from the larger value and keep the sign of the larger value.
Find the value of -7 + (-5).
Answer: -12
Find the value of 14 - (-8).
Answer: 22
Start with the warm-up and go as far as you can. The stretch questions are meant to be hard.
Part 2 of 4 · learn, see, practise
Integers are closed under addition and subtraction, meaning the result is always an integer.
Addition is commutative because changing the order of numbers gives the exact same sum.
Zero is the additive identity because adding zero to any integer does not change its value.
Verify the commutative property for -6 and 9.
Answer: 3
Find the additive inverse of -17.
Answer: 17
Start with the warm-up and go as far as you can. The stretch questions are meant to be hard.
Part 3 of 4 · learn, see, practise
The product of two integers with the same sign is always a positive integer.
The product of two integers with opposite signs is always a negative integer.
The distributive property states that a × (b + c) = (a × b) + (a × c).
Calculate: (-7) × (-8).
Answer: 56
Solve using distributive property: 15 × (-4) + 15 × (-6).
Answer: -150
Start with the warm-up and go as far as you can. The stretch questions are meant to be hard.
Part 4 of 4 · learn, see, practise
Dividing two integers with the same sign gives a positive quotient.
Dividing two integers with different signs gives a negative quotient.
Dividing zero by any non-zero integer equals zero, but division by zero is undefined.
Calculate: (-72) ÷ 8.
Answer: -9
Calculate: (-60) ÷ (-12).
Answer: 5
Start with the warm-up and go as far as you can. The stretch questions are meant to be hard.
Watch out
Remember that subtracting a negative number changes the sign to addition: -5 + 3 = -2.
Use the sign rule: two negatives multiplied together always make a positive.
Any number divided by zero is undefined, whereas zero divided by a non-zero number is zero.
Class activity 1 of 3
Captain Calc needs your help tracking temperatures at the Himalayan Outpost!
Class activity 2 of 3
Help Captain Calc calculate ledger balances at the Super Math Bank!
Class activity 3 of 3
Decode the secret coordinates of Captain Calc's submarine using integer operations!
After class · project
Track temperature fluctuations in five Indian hill stations and calculate average integer changes.
What to make: A temperature log report with complete integer calculations and sign steps shown.
Stretch: Graph the temperature values on a vertical number line showing positions above and below zero.
| Look for | Done well when |
|---|---|
| Data Collection | Accurately lists 5 temperatures using proper integer signs. |
| Calculation Accuracy | Correctly computes temperature sum of integers. |
| Average Calculation | Uses integer division correctly to find the mean temperature. |
Copy it onto paper or print the practice sheet.
City 1 Temperature: ___ degrees C City 2 Temperature: ___ degrees C City 3 Temperature: ___ degrees C Total sum of temperatures: ___ degrees C Average minimum temperature: ___ degrees C
Homework
Try each on paper, then tap to see the answer and working. Or print the practice sheet.
-32: Add absolute values 14 + 18 = 32 and attach the common negative sign.
40: Rewrite subtraction of negative as 25 + 15 = 40.
72: Multiplying two negative integers gives a positive product.
-9: Dividing negative by positive gives a negative quotient.
-150: Rewrite as (-15) × (8 + 2) = (-15) × 10 = -150.
31: Calculate (12 × 3) + (5 × -1) = 36 - 5 = 31.
🔥 Challenge round · finished early?
Cover the notes and try these from memory. They are meant to make you think hard: draw, try small cases, and check your answer.
Determine whether the product of 99 negative integers and 5 positive integers is positive or negative. Explain why without calculating the actual product.
Talk it through or use the drawing board. There is more than one way to get there.
Quiz · 10 questions
Pick an answer to see if it is right and why. Your best score is saved on this device.
🖨 Print what we learned
Pick what to practise, then print it or choose Save as PDF in the print window to download it.
For parents and teachers
Use it as it is, or stretch any part over two sessions. Each row links to the part of the page you need.
| Time | Part | The teacher | The learner |
|---|---|---|---|
| 0–3 min | Warm-up | Ask the question and wait for a guess before any hint. | Guess, then explain. |
| 3–8 min | Warm-up games | Play three or four games. Ask for a reason each time. | Vote and say why. |
| 8–16 min | Adding and Subtracting Integers | Explain, then reveal the examples one step at a time. | Practise up to the stretch question. |
| 16–23 min | Properties of Addition and Subtraction | Explain, then show the examples. | Practise. |
| 23–30 min | Multiplying Integers | Explain, then show the examples. | Practise. |
| 30–37 min | Dividing Integers | Explain, then show the examples. | Practise; the stretch can be homework. |
| 37–43 min | Operation Deep Freeze | Let learners work alone; hint only after a wrong check. | Solve and check. |
| 43–48 min | The Bank Vault Mission | Do the first item together. | Finish the activity. |
| 48–54 min | Submarine Navigation Code | Set as homework if time is short. | Solve the mission. |
| 54–59 min | Quiz | Read each question aloud; vote, then check. | Answer and read why. |
| 59–60 min | Set the project | Show the template and agree a due date. | Start the project. |
Use two-sided colored counters where green represents +1 and red represents -1. Pair one green and one red counter to form zero pairs when adding or subtracting.
Determine whether the product of 99 negative integers and 5 positive integers is positive or negative. Explain why without calculating the actual product.
FAQ
Multiplying by a negative flips the direction on a number line. Flipping direction twice restores the original positive direction.
An integer includes a sign indicating direction, while absolute value measures only distance from zero without sign.
Dividing by zero has no meaningful integer answer because no number multiplied by zero can equal a non-zero number.
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