New NCERT textbook · Class 6 Maths
Ganita Prakash, period by period — fitted to your timetable.
Tell Meyy your periods and their length; it plans every chapter of Ganita Prakash to fit, and you tick off sections as you teach.
Chapter 6 · Period 1 of 21 · 40 min
What Is a Perimeter? Boundary Sums for Rectangles and Squares
Perimeter · Inductive
Students sometimes write P = l × b (confusing perimeter with area) — emphasise boundary vs. region by having them physically trace the edge of a book. The worked examples move from rectangle to square; encourage students to see the square formula as a special case of the rectangle formula where l = b.
0–8Open with a concrete question: ask students how much ribbon is needed to go all the way around a rectangular card. Students trace the boundary with a finger, counting sides. Establish that perimeter is the total boundary distance — the sum of all side lengths — and that opposite sides of a rectangle are equal, so the four-side sum collapses to 2 × (l + b).
8–18Walk through Example (lace around tablecloth), section 6.1 p.131 ("Akshi wants to put lace all around a rectangular tablecloth....") and Example (Usha runs three rounds), section 6.1 p.131 ("Find the total distance Usha travels if she takes three rounds...."). For the square park example, invite students to first guess the formula for a square's perimeter before confirming P = 4 × side.
18–32Students attempt Figure it Out Q1a, section 6.1 p.132 ("Find missing length of a rectangle whose perimeter is 14 cm...."), Figure it Out Q1b, section 6.1 p.132 ("Find the side length of a square whose perimeter is 20 cm...."), and Figure it Out Q1c, section 6.1 p.132 ("Find missing breadth of a rectangle whose perimeter is 12 m....") in pairs, working backwards from the perimeter formula to find the unknown dimension.
32–40Pairs share answers; the teacher collects and records the three formulas — rectangle, square, triangle — on the board as a reference students copy. Close with a quick oral check: the teacher names a shape and students call out the formula.
Assessment
Figure it Out Q1a, section 6.1 p.132 — Find missing length of a rectangle whose perimeter is 14 cm and breadth is 2 cm.
A rectangle has a perimeter of 18 cm and a breadth of 3 cm. What is its length?
- A 6 cm
- B 9 cm
- C 12 cm
- D 15 cm
A. 6 cm
What each wrong option reveals
- B The student correctly computed half the perimeter (9) but did not subtract the breadth, treating 9 as the length.
- C The student halved the perimeter (18 ÷ 2 = 9) but then subtracted breadth from 9 incorrectly as 9 − 3 = 6 — wait, this gives 6; the student who chooses 12 likely added breadth instead: 9 + 3 = 12.
- D The student subtracted only breadth from perimeter (18 − 3 = 15) without dividing by 2, omitting the factor of 2 in the formula.
Chapter 6 · 21 periods of 40 min
Also saved as 13 periods or 17 periods.
- 2Triangle Perimeters and Regular Polygon Generalisations
Perimeter - 3Concentric Tracks and Positional Reasoning on Rectangular Paths
Perimeter - 4Measuring Irregular Shapes and Straight vs Diagonal Units on Dot Grids
Perimeter - 5Split and Rejoin — How Reconfiguring a Rectangle Changes Its Boundary
Perimeter - 6Nine-Square Arrangements — Exploring the Range of Achievable Perimeters
Perimeter - 7Area Formulas for Rectangles and Squares — Direct and Composite Problems
Area - 8Area in Context — Coconut Groves, Composite Figures and Splitting into Rectangles
Area - 9Tangram Area Comparisons — Reasoning Without Formulas
Area - 10Why Squares? Tiling Arguments and the Fixed-Area Rectangle Exploration
Area - 11Area Estimation on Grid Paper and Partial-Square Conventions
Area - 12House Floor Plans — Recovering Missing Dimensions and Computing Total Area
Area - 13Area Maze Puzzles — Multi-Step Reasoning with Sub-Rectangle Areas
Area - 14Cutting a Rectangle to Discover the Triangle Area Formula
Area of a Triangle - 15Non-Right Triangles — Decomposing ABE to Extend the Formula
Area of a Triangle - 16Composite Grid Figures — Splitting into Rectangles and Triangles
Area of a Triangle - 17Perimeter–Area Tension — Designing Shapes with Fixed Area but Different Perimeters
Area of a Triangle - 18Inverse Area Problems and Design Challenges
Area of a Triangle - 19Design Problems — Borders, Inner Rectangles and the Folded-Square Reasoning
Area of a Triangle - 20Mixed-Application Practice — Connecting All Area and Perimeter Techniques
Area of a Triangle - 21Four Problems, One Chapter — Putting Perimeter and Area to Work
Synthesis
Ganita Prakash · Class 6 · 10 chapters
Any 3 chapters free · no payment details · then introductory offer ₹499 per subject-stage, per year.