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Numbers up to 3 Digit
3digit numbers begin with 100 and end on 999. These numbers consist of 3 digits in which the first digit should be 1 or greater than 1 and the remaining 3 digits can be any number from 0 to 9. Learning 3digit numbers is the building block for higherdigit numbers. Let us explore more about the importance, formation, and place value of numbers up to 3 digit.
What are 3Digit Numbers?
3digit numbers are those numbers that consist of only 3 digits. They start from 100 and go on till 999. For example, 673, 104, 985 are 3digit numbers. It is to be noted that the first digit of a threedigit number cannot be zero because in that case, it becomes a 2digit number. For example, 045 becomes 45.
Place Value of 3Digit Numbers
Every threedigit number’s value can be found by checking the place value of each digit. Let us consider the number 243. The first digit at the rightmost position is said to be at units place, so it will be multiplied by 1. Hence, the product is 3 × 1 = 3. Then the second number is 4, and because it is at tens place, it is multiplied by 10. The value, therefore, is 4 × 10 = 40. The third number 2 is at the hundreds place. So 2 is multiplied by 100 and its value is 2 × 100 = 200. Therefore the number is 200 + 40 + 3 = 243.
Decomposing a 3digit number: In a threedigit number, there are three place values used – hundreds, tens, and units. Let us take one example to understand it better. Here, 465 is a threedigit number and it is decomposed in the form of a sum of three numbers. As 5 is on the units place, 60 is on the tens place and 400 is on the hundreds place.
Significance of Zero in 3digit numbers: The number zero does not make any contribution to a 3digit number if it is placed in a position where there are no other nonzero numbers to its left. So how is 303 different from 033 or even 003? In 033, the values are (0 × 100) + (3 × 10) + (3 × 1) = 0 + 30 + 3= 33 which means that the number actually becomes a 2digit number, i.e., 33, or in the case of 003, it becomes a singledigit number, i.e., 3. In these two examples, the zero does not contribute any value to the number, so the numbers can be expressed as 33 or 3 as well.
Expanded Form of 3Digit Numbers
The expanded form of a 3digit number can be expressed and written in three different ways. Consider a threedigit number 457. The number 457 can be written in one form as 457 = (4 × hundreds) + (5 × tens) + (7 × ones). In the second way, the number 457 can be written as 457 = (4 × 100) + (5 × 10) + (7 × 1). And finally the number 457 can be expanded in the form as 457 = 400 + 50 + 7. All the three ways of writing numbers in the expanded form are correct. Writing a 3digit number in the expanded form helps to know the constituents of the number.
Basically splitting or expanding a 3digit number helps us to understand more about the 3digit number. By splitting we know the number of hundreds, tens, and units available in the 3digit number.
Important Notes on 3digit Numbers
 100 is the smallest 3digit number and 999 is the greatest 3digit number.
 A 3digit number cannot start with 0.
 10 tens make 1 hundred which is the smallest 3digit number and 10 hundred make a thousand which is the smallest 4digit number.
 A 3digit number can also have two zeros but the two zeros should be in the tens place and the units place, for example, 100, 200, 300, 400. It is to be noted that the zeros cannot be in the hundreds place because in that case it becomes a 2digit number. For example, 067 becomes 67.
Common Mistakes of Numbers up to 3Digits
Some of the common mistakes are observed while writing or reading a 3digit number. These mistake in reading and interpreting a 3digit number is often understood as some other number. In the process of reading, writing, and interpreting a 3digit number, the place value of the digits should be rightly interpreted. Here we have listed below the three common mistakes often committed by children in writing threedigit numbers.
 Misconception 1: Children make mistakes identifying numbers when there is a zero in the units place or tens place. Example: When asked to read 130 and 103, students may get confused. It helps them to model the numbers through Base10 blocks. That way they can see the ten’s and one’s place value explicitly.
 Misconception 2: When asked to write “one hundred twentythree," students often write 100 first and then attach 23 to it thus ending up with the number “10023” Fact: This misconception arises due to a superficial understanding of place values. Using the base10 blocks or abacus show children that a digit has different values based on its position.
 Misconception 3: Sometimes when asked to form the smallest 3digit number given three digits that include zero, children place the zero in the leftmost position. Fact: This is incorrect. Zero cannot be in the hundreds place if we are creating a 3digit number. For example: the smallest 3digit number using all digits of 5, 0, and 7 is 507 and not 057
Operations on Numbers up to 3Digits
The four arithmetic operations of addition, subtraction, multiplication, and division can be conveniently performed across 3digit numbers. In the process of performing these arithmetic operations, the place value of the corresponding number should be rightly matched. An error in matching the place value could result in wrong answers. Here we shall look at a simple activity using 3 digit numbers, to help us understand the changing pattern in each of the digits of the hundredth place, ten's place, and unit's place. This activity shall help in a better understanding of the learning needed for the 3 digit numbers.

Get students to skip count by 10 and 100 to build fluency with 3digit numbers. First, start at 100. Then start from any random 3digit number like 136.

Help children spot the pattern that when skip counting by 10, the digit in the ones place value does not change. Similarly, when skip counting by 100, the digits in the ones place and tens place does not change.

Use a 100square grid to build fluency. Let students spot the pattern that moving one row up or down is the same as skip counting by 10. Moving columns (left or right) increases or decreases numbers by 1.

Often children are given three digits and asked to find the largest and smallest number threedigit number using all digits. The trick here is to arrange all digits in descending order to find the largest number.
To find the smallest number, arrange all digits in ascending order. But keep in mind that if zero is one of the digits, it cannot be placed to the left. E.g. Using the digits 7, 3, and 6, the largest number is 763 (digits in descending order) and the smallest number is 367 (digits in ascending order). Using the digits 4, 0, and 8, the largest number will be 840 but the smallest 3digit number is 408 and not 048.
Smallest 3Digit Number
The smallest 3digit number is 100 because its predecessor is 99 which is a twodigit number. 3digit numbers start from 100 and end on 999.
Greatest 3Digit Number
The greatest 3digit number is 999 because its successor is 1000 which is a fourdigit number. 3digit numbers start from 100 and end on 999.
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Examples on 3Digit Numbers

Example 1: How many 3digit numbers are there?
Solution:
There are 900 threedigit numbers in all. This can be calculated using the following method.
 Step 1: Write the largest and the smallest 3digit numbers. We know that the largest 3digit number is 999. The smallest 3digit number is 100.
 Step 2: Find the difference between them. Their difference is, 999  100 = 899
 Step 3: Add 1 to the difference. This means 899 + 1 = 900. Therefore, there are 900 threedigit numbers in all.

Example 2: Solve the puzzle: Add the smallest 2digit number to the smallest 1digit number. Subtract the sum from one less than the greatest 3digit number.
Solution:
The smallest 2digit number = 10. The smallest 1digit number = 1. The sum of these two numbers is 10 + 1 = 11. One less than the greatest 3digit number is 998. On subtracting 11 from 998, we get. 998  11 = 987.

Example 3: Find the greatest 3digit number which is a perfect square.
Solution: The greatest 3digit number which is a perfect square is 961 because 31^{2} = 961.
FAQs on Numbers up to 3digits
How Many 3Digit Numbers are there?
There are a total of 900 threedigit numbers. These include the smallest 3 digit number  100 to the largest 3 digit number  999. The numbers beyond these 3digit numbers are the 4digit numbers, and the numbers less than the 3digit numbers are 2digit numbers.
Which is the Largest 3 Digit Number?
The largest 3digit number is 999. Adding 1 more to it will make it a 4digit number, that is, 1000.
What is the Sum of the Three Largest 3 Digit Numbers?
The three largest 3digit numbers are 997, 998, 999. Their sum is 2994 as 997 +998 +999 = 2994.
What is the Smallest 3Digit Number?
The number 100 is the smallest 3digit number. Subtracting 1 from it makes it a 2digit number. There are a total of 900 threedigit numbers, of which the number 100 is the smallest 3digit number.
How Many Even 3Digit Numbers are there?
There are a total of 900 3digit numbers. Of these half of them are even numbers and the remaining half are odd numbers. Hence there are 900/2 = 450 even 3digit numbers.
Can a 3Digit Number have Two Zeros?
A 3digit number can have two zeros. The two zeros should be in the tens place and the units place. Some of the examples of 3digit numbers with two zeros are 100, 200, 300, and 400. It should be noted that the hundreds place in a 3digit number cannot have the number 0 because that will make it a 2digit number. For example, 098 becomes 98.
Which is the Smallest 3 Digit Number Divisible by 4?
The smallest 3digit number is 100 and we know that it is divisible by 4 because 100/4 = 25. Therefore, we can say that 100 is the smallest 3digit number which is divisible by 4.
Which 3 Digit Number has the Most Factors?
The 3digit number that has the most factors is 840. The factors of 840 can be listed as, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 15, 20, 21, 24, 28, 30, 35, 40, 42, 56, 60, 70, 84, 105, 120, 140, 168, 210, 280, 420 and 840.
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