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Fun with Numbers - Number Names up to 1000

Grade 3CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Understanding 3-Digit Numbers: A 3-digit number consists of three places: Hundreds, Tens, and Ones. For example, in the number 456456, 44 is in the hundreds place, 55 is in the tens place, and 66 is in the ones place. Visually, imagine an abacus with three spikes where the leftmost spike represents hundreds, the middle represents tens, and the rightmost represents ones.

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Place Value Blocks: Numbers up to 10001000 can be represented using base-ten blocks. A large square 'flat' represents 100100, a long 'rod' represents 1010, and a small 'unit' cube represents 11. To show 234234, you would use 22 flats, 33 rods, and 44 unit cubes.

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Writing Number Names for Hundreds: When writing the name for a number like 300300, we say 'Three hundred'. For numbers from 100100 to 900900 in even hundreds, we simply name the digit in the hundreds place and add the word 'hundred'. Visualizing this, 1010 rods of ten grouped together form one large 100100 block.

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Combining Tens and Ones: When writing full number names, we combine the hundreds, tens, and ones. For example, 725725 is written as 'Seven hundred twenty-five'. Notice that we do not use the word 'and' between hundreds and tens in standard modern notation, though it is sometimes seen (e.g., Seven hundred and twenty-five).

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The Role of Zero: If a number has a 00 in the tens or ones place, we skip that place when saying the name. For example, 508508 is 'Five hundred eight' and 420420 is 'Four hundred twenty'. On a place value chart, the 00 acts as a placeholder to keep the other digits in their correct positions.

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Expanded Form: This is a way to write a number as the sum of the values of its digits. For example, the expanded form of 892892 is 800+90+2800 + 90 + 2. This helps in understanding how the number name is constructed: 'Eight hundred' (800800), 'ninety' (9090), 'two' (22).

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Reaching One Thousand: When we add 11 to 999999, we get 10001000. This is the first 4-digit number and its name is 'One thousand'. Visually, imagine stacking 1010 flats of 100100 each to form a large cube representing 10001000 units.

📐Formulae

Value of a Digit=Digit×Place Value\text{Value of a Digit} = \text{Digit} \times \text{Place Value}

Number=(H×100)+(T×10)+(O×1)\text{Number} = (H \times 100) + (T \times 10) + (O \times 1)

Expanded Form of abc=(a×100)+(b×10)+(c×1)\text{Expanded Form of } abc = (a \times 100) + (b \times 10) + (c \times 1)

999+1=1000999 + 1 = 1000

💡Examples

Problem 1:

Write the number name for the numeral 647647.

Solution:

Step 1: Identify the digit in the hundreds place, which is 66. This gives us 'Six hundred'. \ Step 2: Identify the digits in the tens and ones places, which is 4747. This gives us 'forty-seven'. \ Step 3: Combine them together to get 'Six hundred forty-seven'.

Explanation:

To write a number name, we break the number down by its place values (Hundreds, Tens, and Ones) and then write the corresponding words in order.

Problem 2:

Write the numeral for 'Eight hundred five'.

Solution:

Step 1: Look at the 'hundreds' part: 'Eight hundred' means there is an 88 in the hundreds place. \ Step 2: Look for 'tens'. There is no 'tens' name mentioned (like twenty or thirty), so we put a 00 in the tens place. \ Step 3: Look at the 'ones' part: 'five' means there is a 55 in the ones place. \ Step 4: Combine the digits: 805805.

Explanation:

When a specific place value (like tens) is not mentioned in the number name, we must use zero as a placeholder to ensure the other digits stay in their correct places.