Unit 1 · Class 9 IB MYP · Formula Sheet

Real Number System Formulas — Class 9 IB MYP

Classify real numbers, work with surds, and understand the completeness of the number line.

Key Formulas

Number Sets

\mathbb{N} \subset \mathbb{Z} \subset \mathbb{Q} \subset \mathbb{R}

Surds

\sqrt{a} \times \sqrt{b} = \sqrt{ab}

Rationalizing

\dfrac{1}{\sqrt{a}} = \dfrac{\sqrt{a}}{a}

Rationalizing Binomial

\dfrac{1}{a + \sqrt{b}} \times \dfrac{a - \sqrt{b}}{a - \sqrt{b}}

Worked Examples

1Using: Place Value

Find the place value of 6 in 3,65,421.

Step 1: 6 is in the ten-thousands place.

Step 2: Place value = 6 x 10,000 = 60,000.

Answer: 60,000

2Using: Successor

Find the successor of 9,999.

Step 1: Successor = n + 1

Step 2: = 9,999 + 1 = 10,000.

Answer: 10,000

Practice Now

Apply these formulas with 60+ practice questions and AI-powered doubt clearing.

Practice Now

More Class 9 IB MYP Formulas

Quadratic ExpressionsCoordinate GeometryLinear & Non-Linear FunctionsCircle GeometryTrigonometry Introduction3D Geometry

Frequently Asked Questions

How many formulas are in Class 9 IB MYP Real Number System?+
There are 4 formulas in the Real Number System chapter for Class 9 IB MYP. Each formula is essential for solving problems in this topic.
How to remember Real Number System formulas easily?+
Practice regularly with worked examples, group related formulas together, and use SparkEd's interactive practice mode to reinforce your memory through problem-solving.
Are these Real Number System formulas enough for exams?+
Yes, these formulas cover the complete IB MYP Class 9 syllabus for Real Number System. Practice applying them to different types of questions for full exam readiness.

Master Real Number System on SparkEd

Go beyond formulas. Practice at three difficulty levels with instant feedback, step-by-step solutions, and an AI coach.

Start Practising Free

SparkEd Maths provides free formula sheets for Class 1-10 across 7 education boards. All formulas are aligned to the 2025-26 syllabus.