What is financial infrastructure?

The network of banks, payment systems and stock markets that helps manage money

What are the main things a bank does?

Holds deposits and lends money as loans

How do banks make money?

They pay lower interest on deposits and charge higher interest on loans

Earning interest on previous interest as well as on the original amount

How many zeroes are there in one crore?

Seven zeroes — one crore is written as \(1{,}00{,}00{,}000\).

How many lakhs make one crore?

One hundred lakhs make one crore \((100 \times 1{,}00{,}000 = 1{,}00{,}00{,}000)\).

How is one million related to lakhs?

One million equals ten lakhs \((10{,}00{,}000)\); it is 1 followed by six zeroes.

How does the Indian system place commas in 1278830?

As \(12{,}78{,}830\) — twelve lakh seventy-eight thousand eight hundred thirty.

How much less than one lakh is 75000?

It is \(25{,}000\) less, since \(1{,}00{,}000 - 75{,}000 = 25{,}000\).

How many thousands make one lakh?

One hundred thousands make one lakh.

Why is multiplying by 5 the same as dividing by 2 then multiplying by 10?

Because \(5 = \dfrac{10}{2}\), so \(n \times 5 = \dfrac{n}{2} \times 10\).

What is the value of 1 arab?

One arab is \(1\) followed by nine zeroes \((1{,}00{,}00{,}00{,}000)\); it equals 100 crore, which is one billion.

When should we round a large number instead of using its exact value?

When only the approximate size matters, e.g. saying a town has about 75,000 people instead of 76,068.

Large Numbers Around Us

Q: How many zeroes are there in one lakh?

Five zeroes — one lakh is written as \(1{,}00{,}000\).

Class 7 Mathematics · Ganita Prakash Part 1 · Chapter 1

163 members in the CBSE community

View all

CBSE Class 7 · Mathematics

8 chapters: lakhs and crores to fractions

Marks booster + cheatsheet: key concepts in 2 lines each, common traps
Triangle inequality, Ch 7
Angle pairs of parallel lines, Ch 5
Common traps, corrected
Magic squares and Virahāṅka numbers, Ch 6
Brahmagupta's fraction formulas, Ch 8

Page 1 free about 8 min read, Full kit about 55 min read

₹39See the full kit

CBSE Class 7 · MathematicsTrending

Five congruence conditions to equations

Marks booster + cheatsheet: key concepts in 2 lines each
Integer sign rules, Ch 2
HCF and LCM by prime factors, Ch 3
Multiplying and dividing decimals, Ch 4
Mean, median and outliers, Ch 5
Ruler-and-compass constructions, Ch 6

Page 1 free about 8 min read, Full kit about 55 min read

₹39See the full kit

View all 7 amazing Marks Booster kits →

Summary

This chapter builds a feel for very large numbers — lakhs, crores and arabs — and connects them to millions and billions. You learn that \(1\) lakh is \(1\) followed by five zeroes \((1{,}00{,}000)\) and \(1\) crore is \(1\) followed by seven zeroes \((1{,}00{,}00{,}000)\). The Indian system groups digits in a \(3\text{-}2\text{-}2\) comma pattern while the American (International) system groups them uniformly in threes, so \(1\) million equals ten lakhs. You practise reading and writing numbers in both systems, comparing them, and finding "nearest neighbours" (nearest thousand, lakh, crore) by rounding up or rounding down. The chapter stresses that exact values are not always needed — a good estimate often communicates size better. Through thought experiments (Can Mumbai fit in one lakh buses? How many coins stack up to the Statue of Unity?) you sharpen estimation. You also explore multiplication shortcuts such as multiplying by \(5\) being the same as dividing by \(2\) and multiplying by \(10\), and spot patterns in the number of digits a product can have.

Reading and writing large numbersIndian vs American place value systemsExact and approximate values & roundingNearest neighbours and estimationPatterns in products and multiplication shortcuts

Key terms

Lakh

One lakh = \(1{,}00{,}000\), written as 1 followed by five zeroes; equals one hundred thousand.

Crore

One crore = \(1{,}00{,}00{,}000\), written as 1 followed by seven zeroes; equals one hundred lakhs.

Indian place value system

Digit grouping in a 3-2-2 pattern from the right (thousands, lakhs, crores).

American / International system

Digit grouping uniformly in threes (thousands, millions, billions).

Rounding (up / down)

Replacing a number by a nearby convenient value; rounding up gives more, rounding down gives less.

Nearest neighbours

The nearest thousand, ten thousand, lakh, ten lakh and crore to a given number.

Estimation

Finding an approximate value that is close enough for the purpose at hand.

Extra questions & answers

Try one from this chapter

How many zeroes are there in one lakh?

Flashcards & interactive practice