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Formula Sheet

The World of Numbers — Formula Sheet

CBSE · Class 9 · Mathematics

10 formulas from The World of Numbers (CBSE Class 9 Mathematics) on one page, grouped by topic. Part of the CBSE Class 9 Mathematics syllabus.

89 questions76 flashcards10 formulas & key relations5 concepts

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10 Entries · 5 Sections

Formulas and Key Relations

3. Zero and Integers

a + 0 = a; a - 0 = a; a × 0 = 0

5 + 4 = 9; (-5) + (-4) = -9; 7 - 0 = 7; -6 - 0 = -6; (-3) × 4 = -12; (-3) × (-4) = 12

4. Rational Numbers

a/b = c/d if ad = bc

a/b + c/b = (a+c)/b

a/b - c/b = (a-c)/b

a/b × c/d = ac/bd

a/b ÷ c/d = a/b × d/c = ad/bc

Zero and Integers

Brahmagupta defined zero as a - a = 0.

Zero obeys a + 0 = a, a – 0 = a, and a × 0 = 0.

Key relations

Integer rules include 5 + 4 = 9, (-5) + (-4) = -9, (-3) × 4 = -12, and (-3) × (-4) = 12.

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Frequently Asked Questions

What are the important topics in The World of Numbers for CBSE Class 9 Mathematics?
Key topics in The World of Numbers include Growth of Number Systems, Zero and Integers, Rational Numbers, Irrational Numbers. Study these first, then practise questions on each for Class 9 exams.
How many formulas are in The World of Numbers?
This sheet lists 10 formulas from The World of Numbers, grouped by topic. Learn what each symbol stands for so you can apply the formula, not just recall it.
How should I revise The World of Numbers for Class 9 exams?
Learn the core ideas first, then work through the 89 practice questions on The World of Numbers. Revise definitions regularly and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

More resources for The World of Numbers

All CBSE Class 9 Mathematics Formula Sheet

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