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mental calculation MCQ Questions for Class 9

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11 questions tagged with mental calculation.

Question 1/11 Expert Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 64

\( 305^2 \) को पहचान से निकालने पर सही मान क्या है?

What is the correct value of \(305^2\) using an identity?

Explanation opens after your attempt
Correct Answer

A. (93025)सही मान

Step 1

Concept

(3052=(300+5)2=90000+3000+25=93025). Exam tip: add both (2ab) and \(b^2\).

Step 2

Why this answer is correct

The correct answer is A. (93025) / सही मान. (3052=(300+5)2=90000+3000+25=93025). Exam tip: add both (2ab) and \(b^2\).

Step 3

Exam Tip

(3052=(300+5)2=90000+3000+25=93025) होता है। परीक्षा में (2ab) और \(b^2\) दोनों जोड़ें।

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Question 2/11 Expert Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 64

\(998^2\) का सही मान क्या है?

What is the correct value of \(998^2\)?

Explanation opens after your attempt
Correct Answer

A. (996004)सही मान

Step 1

Concept

\(998^2=1000000-4000+4=996004\). Exam tip: subtract \(2\cdot1000\cdot2\).

Step 2

Why this answer is correct

The correct answer is A. (996004) / सही मान. \(998^2=1000000-4000+4=996004\). Exam tip: subtract \(2\cdot1000\cdot2\).

Step 3

Exam Tip

\(998^2=1000000-4000+4=996004\) है। परीक्षा में \(2\cdot1000\cdot2\) घटाएँ।

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Question 3/11 Hard Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 65

\( 997^2 \) का मान क्या है?

What is the value of \( 997^2 \)?

Explanation opens after your attempt
Correct Answer

A. (994009)सही मान

Step 1

Concept

\(997^2=1000000-6000+9=994009\). Exam tip: subtract \(2\cdot1000\cdot3\).

Step 2

Why this answer is correct

The correct answer is A. (994009) / सही मान. \(997^2=1000000-6000+9=994009\). Exam tip: subtract \(2\cdot1000\cdot3\).

Step 3

Exam Tip

\(997^2=1000000-6000+9=994009\) है। परीक्षा में \(2\cdot1000\cdot3\) घटाएँ।

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Question 4/11 Hard Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 63

\( 405^2 \) को पहचान से निकालने पर सही मान क्या है?

What is the correct value of \( 405^2 \) using an identity?

Explanation opens after your attempt
Correct Answer

A. (164025)सही मान

Step 1

Concept

(4052=(400+5)2=160000+4000+25=164025). Exam tip: add both (2ab) and \(b^2\).

Step 2

Why this answer is correct

The correct answer is A. (164025) / सही मान. (4052=(400+5)2=160000+4000+25=164025). Exam tip: add both (2ab) and \(b^2\).

Step 3

Exam Tip

(4052=(400+5)2=160000+4000+25=164025)। परीक्षा में (2ab) और \(b^2\) दोनों जोड़ें।

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Question 5/11 Medium Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 64

\( 58\times42 \) का मान ( (50+8)(50-8) ) से क्या होगा?

What is the value of \( 58\times42 \) using ( (50+8)(50-8) )?

Explanation opens after your attempt
Correct Answer

A. (2436)

Step 1

Concept

\(50^2-8^2=2500-64=2436\). Exam tip: identify the common centre (50).

Step 2

Why this answer is correct

The correct answer is A. (2436). \(50^2-8^2=2500-64=2436\). Exam tip: identify the common centre (50).

Step 3

Exam Tip

\(50^2-8^2=2500-64=2436\)। परीक्षा में समान केंद्र (50) पहचानें।

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Question 6/11 Medium Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 63

\( 103\times97 \) का मान निकालने के लिए कौन सी सर्वसमिका उपयोगी है?

Which identity is useful to calculate \( 103\times97 \)?

Explanation opens after your attempt
Correct Answer

D. ( (a+b)(a-b)=a-2-b-2 )

Step 1

Concept

(103=100+3) and (97=100-3). So the difference of squares identity is simplest.

Step 2

Why this answer is correct

The correct answer is D. ( (a+b)(a-b)=a-2-b-2 ). (103=100+3) and (97=100-3). So the difference of squares identity is simplest.

Step 3

Exam Tip

(103=100+3) और (97=100-3) है। इसलिए अंतर के वर्गों की सर्वसमिका सबसे सरल है।

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Question 7/11 Medium Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 62

\( 97^2 \) का मान ( (100-3)2 ) से क्या होगा?

What is the value of \( 97^2 \) using ( (100-3)2 )?

Explanation opens after your attempt
Correct Answer

A. (9409)

Step 1

Concept

\(97^2=10000-600+9=9409\). Exam tip: note the negative middle term.

Step 2

Why this answer is correct

The correct answer is A. (9409). \(97^2=10000-600+9=9409\). Exam tip: note the negative middle term.

Step 3

Exam Tip

\(97^2=10000-600+9=9409\) है। परीक्षा में घटाव वाले मध्य पद पर ध्यान दें।

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Question 8/11 Easy Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 67

\( 98^2 \) को ( (100-2)2 ) से निकालने पर उत्तर क्या है?

What is the answer for \( 98^2 \) using ( (100-2)2 )?

Explanation opens after your attempt
Correct Answer

B. (9604)

Step 1

Concept

( (100-2)2=10000-400+4=9604 ). Exam tip: keep the subtracted middle term correct.

Step 2

Why this answer is correct

The correct answer is B. (9604). ( (100-2)2=10000-400+4=9604 ). Exam tip: keep the subtracted middle term correct.

Step 3

Exam Tip

( (100-2)2=10000-400+4=9604 )। परीक्षा में घटाने वाले बीच के पद को सही रखें।

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Question 9/11 Easy Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 66

\( 104\times96 \) को किस सर्वसमिका से जल्दी निकाला जा सकता है?

Which identity can quickly calculate \( 104\times96 \)?

Explanation opens after your attempt
Correct Answer

C. ( (a+b)(a-b)=a-2-b-2 )

Step 1

Concept

(104=100+4) and (96=100-4). So the difference of squares identity is useful.

Step 2

Why this answer is correct

The correct answer is C. ( (a+b)(a-b)=a-2-b-2 ). (104=100+4) and (96=100-4). So the difference of squares identity is useful.

Step 3

Exam Tip

(104=100+4) और (96=100-4) है। इसलिए अंतर के वर्गों की सर्वसमिका उपयोगी है।

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Question 10/11 Easy Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 66

\( 99^2 \) को ( (100-1)2 ) से निकालने पर मान क्या होगा?

Using ( (100-1)2 ), what is \( 99^2 \)?

Explanation opens after your attempt
Correct Answer

A. (9801)

Step 1

Concept

( (100-1)2=10000-200+1=9801 ). Exam tip: subtract the middle term in minus identity.

Step 2

Why this answer is correct

The correct answer is A. (9801). ( (100-1)2=10000-200+1=9801 ). Exam tip: subtract the middle term in minus identity.

Step 3

Exam Tip

( (100-1)2=10000-200+1=9801 ) है। परीक्षा में घटाव वाली सर्वसमिका में बीच का पद घटाएँ।

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Question 11/11 Easy Mathematics Exploring Algebraic Identities Algebraic identities Class 9 Level 65

\( 51^2 \) को ( (50+1)2 ) से निकालने पर परिणाम क्या है?

Using ( (50+1)2 ), what is \( 51^2 \)?

Explanation opens after your attempt
Correct Answer

D. (2601)

Step 1

Concept

\(51^2=2500+100+1=2601\). Exam tip: add (2ab) separately.

Step 2

Why this answer is correct

The correct answer is D. (2601). \(51^2=2500+100+1=2601\). Exam tip: add (2ab) separately.

Step 3

Exam Tip

\(51^2=2500+100+1=2601\) होता है। परीक्षा में (2ab) को अलग से जोड़ें।

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