This chapter focuses on the concept of numbers and their different forms. It starts by introducing the number system and the place value of digits in a number. The chapter then covers the comparison of numbers and their properties, such as even and odd numbers, prime and composite numbers, etc. The chapter also covers estimation, rounding off numbers, and the use of brackets.

## Exercise 1.1

### Q1: Fill in the blanks:

(a) 1 lakh = _____________ ten thousand.

(b) 1 million = _____________ hundred thousand.

(c) 1 crore = _____________ ten lakh.

(d) 1 crore = _____________ million.

(e) 1 million = _____________ lakh.

Answers:

(a): 10 ten thousand equals 1 lakh

(b): 1 million equals 10 hundred thousand

(c): 1 crore equals 10 ten lakh

(d): 1 crore equals 10 million

(e): 1 million equals 10 lakh

### Q2. Place commas correctly and write the numerals:

(a) Seventy-three lakh seventy-five thousand three hundred seven.

(b) Nine crores five lakh forty-one.

(c) Seven crore fifty two lakh twenty-one thousand three hundred two.

(d) Fifty-eight million four hundred twenty-three thousand two hundred two.

(e) Twenty-three lakh thirty thousand ten.

Answers:

As you learned (Th, H, T, O), you can easily convert English written numbers into digits

First, we put Ones, then Tens to left, and so on like this table

Ten Thousand | Thousands | Hundreds | Tens | Ones |
---|---|---|---|---|

10,000 | 1,000 | 100 | 10 | 1 |

Ten Crores | Crores | Ten Lakhs | Lakhs |
---|---|---|---|

10,00,00,000 | 1,00,00,000 | 10,00,000 | 1,00,000 |

(a): Seventy-three lakh seventy-five thousand three hundred seven.

In this question, we need to take Ten Lakhs, digits and replace each digit according to the question

73,75,307

(b): 9,05,00,041

(c): 7,52,21,302

(d): 5,84,23,202

(e): 23,30,010.

### Q3. Insert commas suitably and write the names according to the Indian System of Numeration :

(a) 87595762

(b) 8546283

(c) 99900046

(d) 98432701

Answers:

(a) 8,75,95,762 (Eight crores seventy-five lakh ninety-five thousand seven hundred sixty- two)

(b) 85,46,283 (Eighty-five lakh forty-six thousand two hundred eighty-three)

(c) 9,99,00,046 (Nine crores ninety-nine lakh forty-six)

(d) 9,84,32,701 (Nine crores eighty-four lakh thirty-two thousand seven hundred one)

### Q4. Insert commas suitably and write the names according to the International System of Numeration :

(a) 78921092

(b) 7452283

(c) 99985102

(d) 48049831

Answers:

(a) 78,921,092 (Seventy-eight million nine hundred twenty-one thousand ninety-two)

(b) 7,452,283 (Seven million four hundred fifty- two thousand two hundred eighty-three)

(c) 99,985,102 (Ninety-nine million nine hundred eighty-five thousand one hundred two)

(d) 48,049,831 (Forty-eight million forty-nine thousand eight hundred thirty-one)

## Here are the NCERT Solutions for Class 6 Maths Chapter 1:

**Q: Write the greatest and smallest 6-digit numbers using the digits 6, 0, 5, 2, 1, 9.**

A: The greatest 6-digit number using the given digits is 965210, and the smallest 6-digit number using the given digits is 102569.

**Q: Write the Roman numerals for the given numbers: 50, 100, 500, and 1000.**

A: The Roman numerals for the given numbers are: 50 – L, 100 – C, 500 – D, and 1000 – M.

**Q: Write the successor and predecessor of the following numbers: 59, 155, 2011.**

A: The successor and predecessor of the given numbers are:

59: successor – 60, predecessor – 58

155: successor – 156, predecessor – 154

2011: successor – 2012, predecessor – 2010**Q: Write the smallest composite number and the smallest prime number using the digits 2, 3, 5, 0, 1, 7 (each digit used only once).**

A: The smallest composite number using the given digits is 102, and the smallest prime number using the given digits is 17.

**Q: Estimate the sum of 3224 and 6784.**

A: To estimate the sum of 3224 and 6784, we can round off both numbers to the nearest thousand. So, 3224 ≈ 3000 and 6784 ≈ 7000. Therefore, the estimated sum of 3224 and 6784 is 3000 + 7000 = 10000.