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Class 7 Maths · Chapter 10 · NCERT (gegp202)

Operations with Integers: common misconceptions

See the tempting mistake students make in Operations with Integers, why it feels right at first glance, and a worked visual example that shows the right idea.

The tempting mistake & worked visual

What does subtracting a negative do?

Wrong

3 − (−2) = 1

Why it feels right. Subtract means move left, so I moved two places left.

Right

Subtracting −2 reverses the effect of adding −2.

Worked example

Starting at 3, subtracting 2 lands at 1. Subtracting −2 reverses that direction and lands at 5.
  1. On a number line, 3 − 2 takes two steps left to 1.
  2. For 3 − (−2), reverse the two leftward steps represented by −2.
  3. Two steps right from 3 land on 5.

If your child says… (8 concept checks in this chapter)

As you work through Operations with Integers, listen for these everyday misunderstandings and use the prompt alongside each one.

1. Rakesh’s Puzzle: A Number Game See how to teach this step →

If your child says… “Swapping the numbers keeps their difference the same.”

Ask together
After swapping, does the first pile have extra coins or fewer coins?
What’s true
First minus second changes sign when unequal numbers exchange places.
2. Carrom Coin Integers See how to teach this step →

If your child says… “I subtract the smaller distance from the larger one.”

Ask together
Does moving just 1 cm right even reach zero?
What’s true
Movement across zero includes the distance on both sides.
3. Multiplication of Integers See how to teach this step →

If your child says… “Three is positive, so the answer must be positive.”

Ask together
If every jump goes left from zero, can the final position be positive?
What’s true
Repeating a negative amount a positive number of times gives a negative total.
4. Patterns in Integer Multiplication See how to teach this step →

If your child says… “The answers stay at zero once the table reaches zero.”

Ask together
Why would removing the next negative group leave the answer unchanged?
What’s true
The same change continues when the first factor passes zero.
5. Applications of Integer Operations See how to teach this step →

If your child says… “I must subtract a loss even when it already has a minus sign.”

Ask together
Would subtracting negative four make this cooling temperature rise?
What’s true
Add a change already written as negative; subtracting it would reverse the loss.
6. Division of Integers See how to teach this step →

If your child says… “I multiply the answer by the first number to check division.”

Ask together
In our multiplication line, which number multiplies q?
What’s true
Multiply the answer by the divisor to recover the number being divided.
7. Expressions Using Integers See how to teach this step →

If your child says… “The outside number multiplies only the first number inside brackets.”

Ask together
If every group has two parts, can multiplying whole groups leave one part unchanged?
What’s true
Each term inside an addition bracket receives the outside multiplier.
8. Multiplication of Many Integers See how to teach this step →

If your child says… “Three factors always give a negative answer.”

Ask together
Which of these three factors actually carry negative signs?
What’s true
Without zero factors, count negative factors alone to choose the product’s sign.

Use this chapter three ways