CBSE MATHEMATICS • SELECTED CENTRAL & STATE COMPETITIVE EXAMS
AIMSSchool of MathematicsAim through AIMS

GANITA PRAKASH · GRADE 7 · PART II · CHAPTER 2

Study Materials

Think first. Use AI purposefully. Verify always.

Concise AIMS notes connected to the textbook ideas. Explore each lesson for its model, example and independent practice.

GUESS — Sum and difference of integers

A sum combines the two values. A difference compares the first value with the second; order matters.

a−b=a+(−b)

Keep a running table of guesses. Check both clues, then swap the pair to see what changes.

Textbook connection: Ganita Prakash · Grade 7 · Part II · Operations with Integers · printed page 24

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MOVE — Number line and carrom-coin movements

A signed movement records magnitude and direction: positive is right, negative is left. Final position is the sum of the movements.

P=a+b

Start from zero, mark the first endpoint, then start the second arrow there. Read the final signed position.

Textbook connection: Ganita Prakash · Grade 7 · Part II · Operations with Integers · printed page 25

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CANCEL — Tokens, subtraction and additive inverse

A +1 token and a −1 token form a zero pair. Adding a zero pair changes the representation, not the value. Subtracting an integer has the same effect as adding its additive inverse.

a+(−a)=0

Represent the starting value. Add only the zero pairs needed. Remove the requested tokens and count what remains.

Textbook connection: Ganita Prakash · Grade 7 · Part II · Operations with Integers · printed page 28

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MODEL — Multiplication using tokens

In this model the first factor tells how many groups to place or remove. A positive first factor places groups; a negative first factor removes groups. The second factor describes each signed group. Start every operation from zero.

4×(−2)=−8

Read both factors separately. For removal, add enough zero pairs first. Remove the requested sign, then count the remaining tokens.

Textbook connection: Ganita Prakash · Grade 7 · Part II · Operations with Integers · printed page 29

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PATTERN — Discover sign rules and multiplication by ±1

The token model and consistent product patterns explain the sign rules. For two nonzero factors, equal signs give a positive product and different signs give a negative product. A zero factor gives zero.

1×a=a;(−1)×a=−a

Continue a product pattern through zero. Check the change at each step. Use multiplication by −1 to connect a number with its additive inverse.

Textbook connection: Ganita Prakash · Grade 7 · Part II · Operations with Integers · printed page 32

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REVERSE — Division as reverse multiplication

Division asks for a missing factor. Check a quotient by multiplying it by the divisor. Division by zero is undefined, and dividing two integers need not give an integer.

b×q=a;b≠0

Rewrite the division as a missing-factor multiplication. Find the factor and check the product. Always check that the divisor is nonzero.

Textbook connection: Ganita Prakash · Grade 7 · Part II · Operations with Integers · printed page 38

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CONNECT — Properties and expressions

Multiplication of integers is commutative and associative, and distributes over addition. These properties help reorganise expressions without changing their value.

a×(b+c)=a×b+a×c

Respect brackets first. Use a named property to rearrange or expand. Evaluate both forms to check the connection.

Textbook connection: Ganita Prakash · Grade 7 · Part II · Operations with Integers · printed page 39

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MASTER — Applications, pattern machines and reasoning

Use signed quantities to model a situation. State what positive and negative mean, form an expression, then interpret the result. Testing several cases can support a conjecture but does not prove every case.

30×5+20×(−2)=110

Translate the situation into signed quantities. Write the expression before calculating. Check the result against the original conditions.

Textbook connection: Ganita Prakash · Grade 7 · Part II · Operations with Integers · printed page 35

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