NCERT Ganita Prakash, Class 8, textbook pages 1–32 (Part 2)

How to teach Class 8 Maths Part 2 Chapter 1, Fractions in Disguise, at home

Percentages, discounts and profit and loss, taught with things you already have at home: a 30-minute activity, a game for the week, a 5-day plan and the mistakes to watch for.

¾ = 0.75 = 75%25% off ₹1200= ₹900

NCERT Class 8 Maths Part 2 Chapter 1 Fractions in Disguise: what it teaches

Percentages are fractions out of 100. Your child converts between fractions, decimals and percentages, finds percentages of amounts, and solves discount, profit and loss, and simple interest problems.

Why it matters later. Percentages are used in data, money, science and everyday decisions.

See it: this chapter in pictures

20% of ₹85010% = ₹8520% = ₹170
Find 10%, then double.
cost ₹400, sell ₹460profit ₹6060/400 = 15%
Profit % is on the cost price.
SI = P × R × T ÷ 100₹5000 at 8% for 2 years= ₹800
Simple interest grows by the same amount each year.

You need

  • shop sale flyers
  • a calculator
  • a bill with GST

Tonight’s 30 minutes

  1. Convert ¾ to a decimal and a percentage (0.75, 75%).
  2. Find 20% of ₹850 by finding 10% first.
  3. A shirt marked ₹1200 has 25% off. Sale price?
  4. Bought at ₹400, sold at ₹460: profit percent?

Words to use

  • percent
  • discount
  • profit
  • loss
  • marked price
  • cost price
  • simple interest

Watch for

  • Finding percent of the wrong amount. Profit % is on cost price, discount % on marked price.
  • Adding percentages of different amounts. Work each amount separately.

What it sounds like at home

A short example of the conversation. Your words will differ; the questions are what matter.

You25% off ₹1200. Sale price?

Your child25% is ₹300, so ₹900.

A game for this week: Sale hunter

  1. Collect sale ads.
  2. Work out actual prices after discounts.
  3. Find the best deal.
  4. Explain the reasoning.

A 5-day plan, 30 minutes a day

  1. Day 1Fractions ↔ percentages.
  2. Day 2Percent of an amount.
  3. Day 3Discounts.
  4. Day 4Profit and loss.
  5. Day 5Sale hunter game.

Everyday moments to practise

  • Sales and discounts.
  • Exam percentages.
  • Bank interest.
  • GST on bills.

Quick check

Ask these at the end of the week. Tap to see the answer.

20% of ₹850?

₹170.

25% off ₹1200?

₹900.

Profit % buying at ₹400, selling at ₹460?

15%.

Ready for the next chapter when your child…

  • Converts between fractions, decimals, percentages.
  • Solves discount and profit problems.
  • Uses percentages in real life.

Activities, wording and illustrations are Mathify Kids’ own, following the topics of NCERT’s Ganita Prakash (Class 8). See the full Class 8 parent guide for every chapter.

Questions parents ask

How do I find 20% quickly?

Find 10% by dividing by 10, then double it.

Is profit % on cost or selling price?

On cost price.

What is simple interest?

Interest = principal × rate × time ÷ 100.