CBSE · Class 7
Maths Formulas Class 7
All key formulas and rules for CBSE Class 7 Mathematics
Ch 1.Integers
| Formula / Relation | Expression |
|---|---|
| Addition of integers (same sign) | a + b = |a| + |b| (keep the sign) |
| Addition of integers (different sign) | a + (−b) = |a| − |b| (sign of larger) |
| Multiplication of integers | (+) × (+) = (+); (−) × (−) = (+); (+) × (−) = (−) |
| Division of integers | Same rules as multiplication for signs |
| Additive inverse | a + (−a) = 0 |
Ch 2.Fractions and Decimals
| Formula / Relation | Expression |
|---|---|
| Multiplication of fractions | a/b × c/d = (a×c)/(b×d) |
| Division of fractions (reciprocal) | a/b ÷ c/d = a/b × d/c |
| Multiplication of decimals | 0.a × 0.b: multiply as integers, place decimal |
| Division of decimal by whole number | a.b ÷ n = (ab ÷ n) with decimal adjustment |
Ch 3.Simple Equations
| Formula / Relation | Expression |
|---|---|
| Solving: variable on one side | ax + b = c ⟹ ax = c − b ⟹ x = (c − b)/a |
| Transposition rule | Move term to other side with sign change |
Ch 4.Lines and Angles
| Formula / Relation | Expression |
|---|---|
| Complementary angles | ∠A + ∠B = 90° |
| Supplementary angles | ∠A + ∠B = 180° |
| Linear pair | ∠A + ∠B = 180° (adjacent angles on straight line) |
| Vertically opposite angles | ∠A = ∠C, ∠B = ∠D (when two lines intersect) |
| Alternate interior angles (parallel lines) | ∠A = ∠B |
| Co-interior angles (parallel lines) | ∠A + ∠B = 180° |
Ch 5.Triangle and Its Properties
| Formula / Relation | Expression |
|---|---|
| Angle sum of triangle | ∠A + ∠B + ∠C = 180° |
| Exterior angle theorem | Exterior angle = sum of two non-adjacent interior angles |
| Triangle inequality | Sum of any two sides > third side |
| Pythagorean theorem (right triangle) | a² + b² = c² |
| Pythagorean triplets | 3,4,5 | 5,12,13 | 8,15,17 | 7,24,25 |
Ch 6.Comparing Quantities
| Formula / Relation | Expression |
|---|---|
| Percentage | % = (part/whole) × 100 |
| Converting fraction to % | a/b × 100 |
| Profit | Profit = SP − CP |
| Loss | Loss = CP − SP |
| Profit % | Profit% = (Profit/CP) × 100 |
| Loss % | Loss% = (Loss/CP) × 100 |
| Simple Interest | SI = (P × R × T)/100 |
| Amount (SI) | A = P + SI |
Ch 7.Perimeter and Area
| Formula / Relation | Expression |
|---|---|
| Area of triangle | A = ½ × b × h |
| Area of parallelogram | A = b × h |
| Circumference of circle | C = 2πr = πd |
| Area of circle | A = πr² |
Ch 8.Exponents and Powers
| Formula / Relation | Expression |
|---|---|
| aᵐ × aⁿ | aᵐ⁺ⁿ |
| aᵐ ÷ aⁿ | aᵐ⁻ⁿ |
| (aᵐ)ⁿ | aᵐⁿ |
| aᵐ × bᵐ | (ab)ᵐ |
| a⁰ | 1 |
Frequently Asked Questions
What are the most important formulas in Class 7 Maths?
The most important Class 7 formulas are: (1) Simple Interest (SI = PRT/100), (2) Profit and Loss percentages, (3) Pythagorean theorem (a²+b²=c²), (4) Area of triangle (½×b×h), (5) Circumference and area of circle, (6) Laws of exponents. These appear in exams most frequently and are reused in Class 8–10.
How to memorise Maths formulas for Class 7 exam?
Best approach: (1) Write each formula on a small card (flashcard), (2) Group formulas by chapter, (3) Recite formulas aloud before solving practice problems, (4) Make a formula summary sheet and revise it every 3 days before the exam, (5) Use formulas in at least 5 practice problems each — application reinforces memory.
Is Pythagorean theorem in Class 7 syllabus?
Yes — the Pythagorean theorem (a² + b² = c²) is introduced in Class 7 Chapter 6 (The Triangle and Its Properties). Students are expected to identify right-angled triangles and verify Pythagorean triplets. The full proof and deeper applications come in Class 10.
What is the formula for Simple Interest in Class 7?
Simple Interest (SI) = (P × R × T) / 100, where P = Principal amount, R = Rate of interest per year (%), T = Time in years. Amount = Principal + Simple Interest. This formula is in Chapter 8 (Comparing Quantities) and is very commonly tested in exams.
Are there any new formulas in Class 7 that weren't in Class 6?
Yes — several new formulas appear in Class 7 that weren't in Class 6: Pythagorean theorem, angle sum property (triangle), exterior angle theorem, Simple Interest, Profit/Loss percentages, area of circle (πr²), and circumference (2πr). Laws of exponents are also new in Class 7.
Related resources
Get Expert Maths Help for Class 7
Build formula fluency and problem-solving skills with experienced CBSE Maths tutors. Strong Class 7 Maths makes Class 9 straightforward.
Find a Maths TutorFor reference only. Formulas and information on this page may contain errors or may have been updated since publication. Always verify against your official NCERT textbooks, board-prescribed materials, or the relevant official source before use in exams or assessments. Learnizo is not responsible for any inaccuracies.