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Number - Place Value up to 10,000

Grade 3IB

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

🔑Concepts

Place Value Columns: Every four-digit number is made of Thousands (ThTh), Hundreds (HH), Tens (TT), and Ones (OO). Imagine a grid where each digit has its own house; the value of a digit depends on which house it lives in. For example, in 4,5214,521, the 44 is in the Thousands house.

Base-10 Visual Representations: We can visualize numbers using blocks. A large 'cube' represents 1,0001,000, a flat 'square' represents 100100, a 'rod' represents 1010, and a tiny 'unit cube' represents 11. To show 2,3412,341, you would draw 22 large cubes, 33 flats, 44 rods, and 11 unit cube.

Expanded Form: This is writing a number to show the value of each digit as an addition sentence. For the number 8,7638,763, the expanded form is 8,000+700+60+38,000 + 700 + 60 + 3. It helps us see exactly how much each part of the number is worth.

Comparing and Ordering: To find which number is bigger, we compare digits starting from the left (Thousands). If the Thousands are the same, we look at the Hundreds, and so on. We use the 'alligator mouth' symbols: >> (greater than), << (less than), and == (equal to).

Rounding to the Nearest 1,000: Visualize a number on a hill. If the Hundreds digit is 0,1,2,3,0, 1, 2, 3, or 44, the number slides back down to the current thousand. If the Hundreds digit is 5,6,7,8,5, 6, 7, 8, or 99, it has enough energy to climb over the peak to the next thousand.

Partitioning: Numbers can be split in different ways, not just by place value. For example, 1,5001,500 can be partitioned into 1,000+5001,000 + 500, or it can be seen as 1515 Hundreds or 150150 Tens. This is like sharing 1,5001,500 marbles into different sized bags.

Number Line Placement: On a number line from 00 to 10,00010,000, the halfway point is 5,0005,000. Visualizing where a number sits (closer to 00 or closer to 10,00010,000) helps in understanding the magnitude and scale of large numbers.

📐Formulae

TotalValue=(dthousands×1000)+(dhundreds×100)+(dtens×10)+(dones×1)Total Value = (d_{thousands} \times 1000) + (d_{hundreds} \times 100) + (d_{tens} \times 10) + (d_{ones} \times 1)

StandardForm=4,000+300+20+5=4,325Standard Form = 4,000 + 300 + 20 + 5 = 4,325

RoundingRule:If digit5Round UpRounding Rule: If \ digit \ge 5 \rightarrow Round \ Up

Comparing:9,000>8,999Comparing: 9,000 > 8,999

💡Examples

Problem 1:

Write the number 6,2596,259 in expanded form and identify the value of the digit 22.

Solution:

Step 1: Identify the place of each digit. 66 is in the Thousands, 22 is in the Hundreds, 55 is in the Tens, and 99 is in the Ones. Step 2: Write as an addition expression: 6,000+200+50+96,000 + 200 + 50 + 9. Step 3: Determine the specific value of 22. Since it is in the Hundreds place, 2×100=2002 \times 100 = 200.

Explanation:

By breaking the number into its constituent parts, we can see the weight of each digit based on its position.

Problem 2:

Round the number 4,7324,732 to the nearest thousand and the nearest hundred.

Solution:

Step 1 (Nearest Thousand): Look at the Hundreds digit, which is 77. Since 757 \ge 5, we round the Thousands digit up from 44 to 55. Result: 5,0005,000. Step 2 (Nearest Hundred): Look at the Tens digit, which is 33. Since 3<53 < 5, the Hundreds digit stays at 77. Result: 4,7004,700.

Explanation:

Rounding depends on the digit to the immediate right of the place value you are rounding to.