# NCERT Class 6 Maths Chapter 1 ‘Knowing Our Numbers’: Notes and Solutions (Free PDF)

As the name suggests, chapter 1 of CBSE NCERT Maths for Class 6 deals with the study of numbers. It teaches students about the magnitude of numbers, make comparisons, and apply different mathematical operations to them. The chapter also introduces the concept of prime numbers, composite numbers, and so on. With constant practice and solving the exercise questions as well as the practice questions on time, students become good at their understanding of the chapter. In this blog, we will cover the CBSE Class 6 NCERT Maths Chapter 1 Notes and Important Questions in sequence.

Also Read: Main Branches of Mathematics

## CBSE Class 6 NCERT Maths Chapter 1 Notes PDF – Free Download

Here are the notes on the important topics taught in Chapter 1 of the CBSE NCERT Maths for Class 6. Following these, we will provide solutions to the exercise questions.

### Topic 1 – Comparing Numbers

The topic deals with the comparison of numbers in a given set of numbers. The trick and steps to solving such questions are –

1. Look for the total number of digits in the given set of numbers. The number with the maximum digits is the greatest and the one with the least number of digits is the smallest.

Eg – 3452, 953

In the above example, the number 953 has 3 digits so it is the smaller number here and the number 3452 has 4 digits in it, symbolizing it to be a greater number.

1. For numbers with the same number of digits, look for the digits from the left-hand side of the given number. The numbers with the greatest digit on their left are the greatest. Also, for further comparisons, keep looking at the digits to the right of the first digit and arrange them in ascending or descending order based on the same concept above.

Now, with the help of the above topic, you can easily understand the topic “How many numbers you can make?”. You have also learned to arrange the numbers in decreasing and increasing order.

### Topic 2: Introducing 10,000

From the knowledge of previous classes, we know that 99 is the greatest 2-digit number. Similarly, 999 and 9999 are the greatest 3-digit and 4-digit numbers respectively. If we add 1 to any of these numbers, they will not remain the 2-digit, 3-digit or even 4-digit numbers anymore. So, here we are:

Greatest 1-digit number = 9

Greatest 2-digit number = 99

Greatest 3-digit number = 999

Greatest 4-digit number = 9999

Now,

Greatest 1-digit number + 1 = 9 + 1 = 10 = Smallest 2-digit number

Greatest 2-digit number + 1 = 99 + 1 = 100 = Smallest 3-digit number

Greatest 3-digit number + 1 = 999 + 1 = 1000 = Smallest 4-digit number

Greatest 4-digit number + 1 = 9999 + 1 = 10,000 (Ten thousand) = Smallest 5-digit number

So, from the above examples we saw that on adding 1 to the greatest number in a specified digit’s number, we get the smallest number of the next higher digit number.

Key Takeaways: 10,000 is the lowest 5-digit number

Also Read: Maths Formulas for Class 10th

### Topic 3: Revisiting Place Values

Remember how we used to expand the given numbers based on their place value? Well, this step just takes a step further with understanding – how to expand a 5-digit number. But first, let’s expand a 3-digit number to recall the concept. Easy?

352 = 3 ✕ 100 + 5 ✕ 10 + 2 ✕ 1

In the above example, 3 is at the hundreds place, 5 is at the tens place and 2 is at the ones place.

Now, let’s see more places of the number system:

### Topic 4: Use of Commas

In the Indian Numeration System, commas are used to mark thousands, lakhs, and crores. So, the first comma comes after 3 digits from the right, the second comma comes 2 digits later and the third comma comes after the next 2 digits.

For example, 24567890 ⇒ 2,45,67,890 ⇒ the number is read as – two crores forty-five lakhs sixty-seven thousand eight hundred ninety

In the International Numeration System, commas are used to mark thousands and then millions. Here, the denotation of 10 lakhs is replaced by 1 million. So, the first comma comes after 3 digits from the right, followed by the second comma after the next 3 digits.

For example 24567890 ⇒ 24,567,890 ⇒ the number is read as – twenty-four million five  hundred sixty-seven thousand eight hundred ninety

## Important Questions in NCERT Class 6 Maths Chapter 1 PDF – Free Download

Here are the important questions on the important topics taught in Chapter 1 of the NCET Maths for Class 6.

Q 1. Make the greatest and the smallest 4-digit number using any of the 3 below-given digits twice. (9, 0, 5)

Ans.   The given numbers are 9, 0, and 5.

Now, for the smallest 4-digit number, use the smallest given digit twice on the left followed by each succeeding digit. But, here is an exception – we cannot use “0” on the left as then the resulting number won’t be a 4-digit number.

Hence, the smallest number comes out to be 5009.

Similarly, the greatest number comes out to be 9950.

Q 2. Arrange the following numbers in ascending order: 847, 9754, 8320 and 571.

Ans. In ascending order, we begin writing the smallest number first and follow by writing the successively larger number. This gives us a series of numbers that are greater than the preceding one as we move to the right.

As we know, 3-digit numbers are smaller than 4-digit numbers.

So, the smallest number is 571 followed by 847.

The greatest number among the 4-digit numbers is 9754 followed by 8320.

So, in ascending order:

Q 3. Put commas in the following number according to the Indian and International numeric systems. Also, write how this number will be called out based on these two numeric systems. 22546798

Ans. As we know in the Indian Numeric System, we mark thousands, lakhs and crores. So, the commas and name of the given number will be:

However, in the International Numeric System, we mark thousands and then millions. So, the commas and name of the given number will be:

Also Read: Multiplications and Division Word Problems

Q 4. The population of Sundarnagar was 2,35,471 in the year 1991. In the

year 2001, it was found to be increased by 72,958. What was the population of

the city in 2001?

Ans. In 2001, the population of Sundarnagar increased by 72,958 than it was in 1991.

Population of Sundarnagar in 1991 =  2,35,471

Hence, the total population of Sundarnagar in 2001 =  2,35,471 + 72,958 = 3,08,429

Q 5. The number of sheets of paper available for making notebooks is

75,000. Each sheet makes 8 pages of a notebook. Each notebook contains

200 pages. How many notebooks can be made from the paper available?

Ans. Since one sheet of paper makes 8 pages.

75,000 sheets of paper will make = 75,000 ✕ 8 pages = 6,00,000 pages

Now, each notebook contains 200 pages.

So, the number of notebooks prepared from 6,00,000 pages = 6,00,000 ÷ 200 = 3000 notebooks.

Hence, 75,000 sheets of paper will make 3000 notebooks.

This was all about CBSE Class 6 NCERT Maths Chapter 1 Notes and Important Questions: Knowing Our Numbers Free PDF Download. Follow the CBSE Class 6 Maths Notes for more such chapter notes and important questions and answers for preparation for CBSE Class 6 Maths.