The World of Numbers
CBSE · Class 9 · Mathematics
All formulas from The World of Numbers in CBSE Class 9 Mathematics. Key equations, constants, and identities for board exam preparation.
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Formulas
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
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Sources & Official References
- NCERT Official — ncert.nic.in
- CBSE Academic — cbseacademic.nic.in
- CBSE Official — cbse.gov.in
- National Education Policy 2020 — education.gov.in
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
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