Large Numbers Around Us
Class 7 · Mathematics
5 ideas in Class 7 Mathematics, explained in plain words, with games and quizzes to practise.
Lakhs, Crores and Place Value
Part of: Reading and Comparing Large Numbers
Numbers grow beyond ten thousand into lakhs (1,00,000) and crores (1,00,00,000). Each place is ten times the one before, and commas help us read them.
Why it matters. Prices, populations and distances in daily life are often in lakhs and crores, so reading them well helps a child make sense of the world.
Try it in two minutes
- Write 1,00,000 and count the zeroes together.
- Ask your child to read a number like 4,05,030 aloud.
- Say a number in words and ask them to write it with commas.
- Ask how many lakhs make a crore.
Try at home. Find a newspaper number in lakhs or crores and read it aloud together.
Indian and International Systems
Part of: Reading and Comparing Large Numbers
The Indian system puts commas in a 3-2-2 pattern from the right, and the international system uses groups of 3. Million, billion, lakh and crore describe the same numbers in different words.
Why it matters. Children meet both systems in books, news and online. Knowing that they match helps them compare big numbers correctly.
Try it in two minutes
- Write 10,00,000 and 1,000,000 side by side.
- Say what each is called in both systems.
- Convert a few numbers back and forth.
- Ask which is bigger, 60 lakh or 7 million.
Try at home. Look up the population of a country in an atlas and say it in both systems.
Building Numbers with Steps
Part of: Building and Estimating
A number can be made by repeated steps such as +1000, +100 or +10. Using the biggest place buttons first gives the fewest presses, which equals the sum of the digits.
Why it matters. It builds deep place value understanding and shows that big numbers are just many smaller groups.
Try it in two minutes
- Pick 3,200 and ask how many +100 presses it needs.
- Make it a different way with +1000 and +100.
- Pick a bigger number and find the fewest presses.
- Compare the fewest presses with the digits of the number.
Try at home. Use coins or paper slips worth 1, 10, 100 and 1000 to build a number.
Rounding and Estimating Large Numbers
Part of: Building and Estimating
Rounding gives a number that is close and easy to use. We look at the part below the place we round to: half or more rounds up, less than half rounds down.
Why it matters. Estimates help us check answers and decide quickly, such as ordering enough food or judging a crowd.
Try it in two minutes
- Pick a number like 4,73,500.
- Round it to the nearest lakh together.
- Estimate a sum by rounding each number first.
- Talk about when exact numbers are needed.
Try at home. Round the price of a few items you see in a shop to the nearest thousand.
Calculating and Imagining Big Numbers
Part of: Working with Large Numbers
Pairs like 25 x 4 or 125 x 8 make round numbers, and the digits of a product can be predicted from the digits of the factors. Big numbers become clear when we compare them with familiar things.
Why it matters. Quick tricks save time, and checking whether an answer is sensible is a lifelong skill.
Try it in two minutes
- Try 25 x 36 using 25 x 4 = 100.
- Ask how many digits 450 x 32 will have before calculating.
- Ask how many days a million seconds are.
- Check with a calculator.
Try at home. Ask your child how many steps it would take to walk 1 lakh metres.
What your child will practise
- Building Numbers with Steps: Space Quick Fire (Quick Fire)
- Calculating and Imagining Big Numbers: Desert Puzzle (Clue Puzzle)
- Indian and International Systems: Candy Quest (Flip and Match)
- Lakhs, Crores and Place Value: Space Quest (Collect the Answer)
- Rounding and Estimating Large Numbers: Jungle Quest (Collect the Answer)
- Quiz: Building Numbers with Steps (8 questions)
- Quiz: Calculating and Imagining Big Numbers (8 questions)
- Quiz: Indian and International Systems (8 questions)
- Quiz: Lakhs, Crores and Place Value (8 questions)