Samacheer Kalvi Class 5 Maths Solutions Term 1 Chapter 2 Numbers Exercise 2.3

Tamilnadu Samacheer Kalvi 5th Maths Solutions Term 1 Chapter 2 Numbers Ex 2.3

Question 1. Read the following numbers by placing the commas at appropriate periods and write their number names.
a. 15731997
b. 341964
с. 29121972
d. 347810
Answer:
a. 15731997
When we put commas using the Indian system, it becomes \( 1,57,31,997 \).
The number name is: One crore fifty-seven lakhs thirty-one thousands nine hundred and ninety-seven. This way of placing commas helps us read large numbers easily in the Indian numbering system.
b. 341964
When we put commas using the Indian system, it becomes \( 3,41,964 \).
The number name is: Three lakhs forty-one thousands nine hundred and sixty-four.
c. 21921972
When we put commas using the Indian system, it becomes \( 2,19,21,972 \).
The number name is: Two crores nineteen lakhs twenty-one thousands nine hundred and seventy-two.
d. 347810
When we put commas using the Indian system, it becomes \( 3,47,810 \).
The number name is: Three lakhs forty-seven thousands eight hundred and ten.
In simple words: To read big numbers, first place commas correctly (like \( 1,00,000 \) for one lakh). Then, say the number written before each comma, followed by its place value name (crore, lakh, thousand, etc.).

🎯 Exam Tip: Always remember to use the correct period names like 'lakhs' and 'crores' when writing number names in the Indian system, and place commas after every two digits from the right, after the first three digits.

Question 2. Write the place value of 5 in the following numbers.
a. 287500
b. 586012
c. 5869732
d. 5467859
Answer:
a. 287500
In 287500, the digit 5 is in the hundreds place. So, its place value is \( 5 \times 100 = 500 \). The place value tells us how much a digit is worth based on its position.
b. 586012
In 586012, the digit 5 is in the lakhs place (one hundred thousand). So, its place value is \( 5 \times 1,00,000 = 5,00,000 \).
c. 5869732
In 5869732, the digit 5 is in the ten lakhs place (one million). So, its place value is \( 5 \times 10,00,000 = 50,00,000 \).
d. 5467859
In 5467859, there are two fives. The first 5 (from the right) is in the tens place. Its place value is \( 5 \times 10 = 50 \). The second 5 (from the left) is in the lakhs place. Its place value is \( 5 \times 10,00,000 = 50,00,000 \).
In simple words: The place value of a digit shows its worth based on where it sits in a number. For example, 5 in the hundreds place means 500, while 5 in the thousands place means 5000.

🎯 Exam Tip: Always identify the position of the digit (ones, tens, hundreds, thousands, lakhs, crores) and then multiply the digit by its place value to find the correct answer.

Question 3. Write the following in standard notation.
a. 30000 + 3000 + 300 + 30 + 3
b. 200000 + 7000 + 7
c. 8000000 + 70000 + 3000 + 30 + 5
d. 4000000 + 400 + 4
Answer:
a. \( 30000 + 3000 + 300 + 30 + 3 \)
Adding these numbers together gives us \( 33,333 \). Standard notation is just writing the number in its usual, short form.
b. \( 200000 + 7000 + 7 \)
Adding these numbers gives us \( 207007 \), which is written as \( 2,07,007 \) in the Indian system.
c. \( 8000000 + 70000 + 3000 + 30 + 5 \)
Adding these numbers gives us \( 8073035 \), which is written as \( 80,73,035 \) in the Indian system.
d. \( 4000000 + 400 + 4 \)
Adding these numbers gives us \( 4000404 \), which is written as \( 40,00,404 \) in the Indian system.
In simple words: Standard notation means writing a number in its regular, compact form. You just add up all the parts given in the expanded form to get the final number.

🎯 Exam Tip: When converting from expanded form to standard notation, be careful to place zeros in the empty place value positions. For example, if there is no hundreds value, a 0 must be placed in the hundreds place.

Question 4. Write the following numbers in expanded form.
a. 63,570
b. 36,01,478
c. 1,45,70,004
d. 28,48,387
Answer:
a. 63,570
To write 63,570 in expanded form, we break it down by the place value of each digit: \( 60000 + 3000 + 500 + 70 + 0 \). This shows the value of each digit clearly.
b. 36,01,478
In expanded form, 36,01,478 is written as: \( 3000000 + 600000 + 1000 + 400 + 70 + 8 \).
c. 1,45,70,004
In expanded form, 1,45,70,004 is written as: \( 10000000 + 4000000 + 500000 + 70000 + 4 \).
d. 28,48,387
In expanded form, 28,48,387 is written as: \( 2000000 + 800000 + 40000 + 8000 + 300 + 80 + 7 \).
In simple words: Expanded form means breaking a number into a sum of the value of each digit. For example, 123 becomes \( 100 + 20 + 3 \).

🎯 Exam Tip: Ensure that each digit is correctly multiplied by its place value (e.g., thousands, ten thousands, lakhs) and that you include a '0' for any place value where a digit is missing.