CBSE · Class 6
Maths Formulas Class 6
All key formulas and rules for CBSE Class 6 Mathematics — chapter by chapter
Ch 1.Knowing Our Numbers
| Formula / Relation | Expression |
|---|---|
| Place value (ones/tens/hundreds) | 1, 10, 100, 1000, 10000, 100000 |
| Indian number system (Lakhs) | 1 Lakh = 1,00,000 |
| Estimation to nearest 10 | If units digit ≥ 5, round up; else round down |
| Largest n-digit number | 10ⁿ − 1 |
| Smallest n-digit number | 10^(n−1) |
Ch 2.Playing with Numbers (HCF & LCM)
| Formula / Relation | Expression |
|---|---|
| Divisibility rule — 2 | Last digit is 0, 2, 4, 6, or 8 |
| Divisibility rule — 3 | Sum of digits is divisible by 3 |
| Divisibility rule — 9 | Sum of digits is divisible by 9 |
| Divisibility rule — 5 | Last digit is 0 or 5 |
| Divisibility rule — 10 | Last digit is 0 |
| Divisibility rule — 11 | (Sum of odd-place digits) − (Sum of even-place digits) = 0 or ±11 |
| HCF × LCM | HCF(a, b) × LCM(a, b) = a × b |
| Prime factorisation | Express number as product of prime factors |
Ch 3.Fractions
| Formula / Relation | Expression |
|---|---|
| Equivalent fractions | a/b = (a×k)/(b×k) |
| Addition of like fractions | a/c + b/c = (a + b)/c |
| Addition of unlike fractions | a/b + c/d = (ad + bc)/(bd) |
| Fraction of a quantity | a/b of X = (a × X)/b |
| Comparing fractions (cross-multiply) | a/b > c/d if a×d > b×c |
Ch 4.Decimals
| Formula / Relation | Expression |
|---|---|
| Decimal place values | 0.1 = 1/10; 0.01 = 1/100; 0.001 = 1/1000 |
| Converting fraction to decimal | a/10 = 0.a; a/100 = 0.0a |
| Addition/Subtraction of decimals | Align decimal points, then add/subtract |
Ch 5.Mensuration (Perimeter and Area)
| Formula / Relation | Expression |
|---|---|
| Perimeter of rectangle | P = 2(l + b) |
| Perimeter of square | P = 4a |
| Perimeter of triangle | P = a + b + c |
| Area of rectangle | A = l × b |
| Area of square | A = a² |
| Area of triangle | A = ½ × base × height |
Ch 6.Ratio and Proportion
| Formula / Relation | Expression |
|---|---|
| Ratio | a : b = a/b |
| Proportion | a : b :: c : d ⟹ a × d = b × c |
| Unitary method | If 1 unit = x, then n units = n × x |
Ch 7.Algebra (Introduction)
| Formula / Relation | Expression |
|---|---|
| Variable expression | 2n, n + 3, n − 5, 3n + 2 |
| Simple equation | x + a = b ⟹ x = b − a |
Frequently Asked Questions
How many formulas are there in Class 6 Maths?
Class 6 Maths is relatively formula-light compared to higher classes. The key formulas are in Mensuration (perimeter and area), Fractions, and Ratio/Proportion. There are approximately 20–25 core formulas to memorise, plus divisibility rules for HCF/LCM.
What is the most important formula in Class 6 Maths?
The HCF × LCM = a × b relationship and the area/perimeter formulas for rectangles and squares are the most practically important. For Class 6 exams, perimeter and area questions consistently appear in the highest mark questions.
How to remember Maths formulas in Class 6?
To remember Class 6 Maths formulas: (1) Write each formula 5 times after learning it, (2) Make a formula sheet and paste it on your study table, (3) Apply each formula in at least 3 practice problems the day you learn it, (4) Revise the formula sheet weekly.
Is Class 6 Maths easy?
Class 6 Maths is accessible but not trivial. Fractions, integers, and basic algebra are conceptually new for most students. With daily practice of 30–45 minutes, most students can score well. The key is not to skip practice — Maths requires doing, not just reading.
What are the chapters in Class 6 Maths?
CBSE Class 6 Maths has 14 chapters: Knowing Our Numbers, Whole Numbers, Playing with Numbers, Basic Geometrical Ideas, Understanding Elementary Shapes, Integers, Fractions, Decimals, Data Handling, Mensuration, Algebra, Ratio and Proportion, Symmetry, and Practical Geometry.
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