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The World of Numbers

CBSE · Class 9 · Mathematics

Flashcards for The World of Numbers — CBSE Class 9 Mathematics. Quick Q&A cards covering key concepts, definitions, and formulas.

89 questions76 flashcards5 concepts

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Card 1Natural Numbers

What are natural numbers?

Answer

Natural numbers are the counting numbers: 1, 2, 3, 4, and so on. They came from counting objects by one-to-one correspondence. Natural numbers are closed under addition, so adding two natural numbers

Card 2Natural Numbers

प्राकृतिक संख्याएँ क्या होती हैं?

Answer

प्राकृतिक संख्याएँ गिनती की संख्याएँ होती हैं: 1, 2, 3, 4, और इसी तरह आगे। इनका उद्गम वस्तुओं को एक-से-एक संगतता से गिनने से हुआ। प्राकृतिक संख्याएँ जोड़ के लिए बंद होती हैं, इसलिए दो प्राकृतिक संख्या

Card 3Origin of Counting

एक-से-एक संगतता ने प्राकृतिक संख्याओं की उत्पत्ति में कैसे मदद की?

Answer

गिनती करते समय एक वस्तु का मिलान दूसरी एक वस्तु से किया जाता था। उदाहरण के लिए, एक कंकड़ एक गाय के लिए हो सकता था। यदि लौटती हुई हर गाय के लिए एक कंकड़ हटा दिया जाता, तो बचे हुए कंकड़ गायब गायों को दि

Card 4Origin of Counting

How did one-to-one correspondence help in the origin of natural numbers?

Answer

One object was matched with one other object while counting. For example, one pebble could stand for one cow. If one pebble was removed for each returning cow, the remaining pebbles showed missing cow

Card 5Ancient Number Records

What is the Lebombo Bone and why is it important?

Answer

The Lebombo Bone was discovered in the Lebombo Mountains between South Africa and Swaziland and dates back approximately 35,000 years. It has 29 notches and is believed to have been used as a lunar ph

Card 6Ancient Number Records

लेबोम्बो बोन क्या है और यह क्यों महत्वपूर्ण है?

Answer

लेबोम्बो बोन दक्षिण अफ्रीका और स्वाज़ीलैंड के बीच लेबोम्बो पर्वतों में मिला था और इसकी तिथि लगभग 35,000 वर्ष पुरानी है। इसमें 29 खांचे हैं और माना जाता है कि इसे चंद्र चरण-गणक या मासिक धर्म कैलेंडर के

Card 7Ancient Number Records

इशांगो बोन क्या है और इसके खांचे क्या दिखाते हैं?

Answer

इशांगो बोन कांगो लोकतांत्रिक गणराज्य में नील नदी के उद्गम के पास मिला था और इसकी तिथि लगभग 20,000 BCE है। इसमें असममित खांचों के तीन स्तंभ हैं। एक स्तंभ संख्याओं को 11, 13, 17, और 19 में समूहित करता ह

Card 8Ancient Number Records

What is the Ishango Bone and what do its notches show?

Answer

The Ishango Bone was found near the headwaters of the Nile in the Democratic Republic of Congo and dates to around 20,000 BCE. It has three columns of asymmetrical notches. One column groups numbers i

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Frequently Asked Questions

What are the important topics in The World of Numbers for CBSE Class 9 Mathematics?
The World of Numbers covers several key topics that are frequently asked in CBSE Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in The World of Numbers — CBSE Class 9 Mathematics?
Understand the core concepts first, then work through the 89 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.
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There are 76 flashcards for The World of Numbers covering key definitions, formulas, and concepts. Use them daily for 10–15 minutes for best results.

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