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Fun with Numbers - Expanded Form

Grade 3CBSE

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

🔑Concepts

Definition of Expanded Form: Expanded form is a way of writing a number to show the value of each digit. It is expressed as a sum of the place values of its digits. For example, the number 254254 is broken down into its parts based on where the digits sit.

Place Value Chart: To understand expanded form, imagine a table with three columns: Hundreds (H), Tens (T), and Ones (O). For a number like 382382, you would place 33 in the H column, 88 in the T column, and 22 in the O column. This visual helps you see that 33 actually represents 300300.

Value of Digits: The position of a digit determines its actual value. In a 3-digit number, the first digit from the left is multiplied by 100100, the second by 1010, and the third by 11. Visualizing base-10 blocks, a 'hundred' is a large square flat, a 'ten' is a long rod, and a 'one' is a small cube.

Writing the Sum: To write the expanded form, we connect the individual place values using the plus symbol (++). For example, for the number 671671, we identify the values as 600600, 7070, and 11, then write them as 600+70+1600 + 70 + 1.

Zero as a Placeholder: When a number has a 00 in a specific place, its value is 00. In expanded form, we can either write the 00 or skip it, though writing it helps maintain the place value structure. For 503503, the expanded form is 500+0+3500 + 0 + 3, showing there are no tens (an empty Tens column in our mental chart).

Standard Form: This is the normal way we write numbers, like 419419. Converting from expanded form (400+10+9400 + 10 + 9) back to standard form (419419) involves adding the values together or simply placing the digits in their correct H-T-O positions.

📐Formulae

Expanded Form=(Digit in Hundreds Place×100)+(Digit in Tens Place×10)+(Digit in Ones Place×1)\text{Expanded Form} = (\text{Digit in Hundreds Place} \times 100) + (\text{Digit in Tens Place} \times 10) + (\text{Digit in Ones Place} \times 1)

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

Example: 745=700+40+5\text{Example: } 745 = 700 + 40 + 5

💡Examples

Problem 1:

Write the number 836836 in expanded form.

Solution:

Step 1: Identify the place value of each digit. The digit 88 is in the hundreds place, so its value is 8×100=8008 \times 100 = 800. \ Step 2: The digit 33 is in the tens place, so its value is 3×10=303 \times 10 = 30. \ Step 3: The digit 66 is in the ones place, so its value is 6×1=66 \times 1 = 6. \ Step 4: Write the sum of these values: 800+30+6800 + 30 + 6.

Explanation:

We break the number down into its constituent parts (Hundreds, Tens, and Ones) and represent them as a mathematical addition expression.

Problem 2:

Convert the expanded form 500+20+0500 + 20 + 0 into standard form.

Solution:

Step 1: Look at the hundreds value: 500500 means there is a 55 in the hundreds place. \ Step 2: Look at the tens value: 2020 means there is a 22 in the tens place. \ Step 3: Look at the ones value: 00 means there is a 00 in the ones place. \ Step 4: Combine the digits to form the number: 520520.

Explanation:

To find the standard form, we identify the single digit that belongs in each place value position and write them together as one number.