Three-Digit Numbers and Their Values
Grade 2 · Math · Study Guide
Understand how three-digit numbers are built from hundreds, tens, and ones and how to read and write them.
A three-digit number is any number from 100 to 999. The first digit tells us the hundreds, the middle digit tells us the tens, and the last digit tells us the ones. The number 485 has 4 hundreds (400), 8 tens (80), and 5 ones (5), which equals 485.
We can write numbers in different ways. Standard form is just the number: 362. Word form uses words: three hundred sixty-two. Expanded form breaks it apart: 300 + 60 + 2. All three forms represent the same value.
When we order three-digit numbers, we compare from left to right. First look at the hundreds. If those are the same, look at the tens. If the tens are the same, look at the ones. For example, 456 < 465 because the tens digit 5 is less than 6 when the hundreds (4) are equal.
| Number | Standard Form | Expanded Form | Word Form |
|---|---|---|---|
| 521 | 521 | 500 + 20 + 1 | Five hundred twenty-one |
| 304 | 304 | 300 + 0 + 4 | Three hundred four |
| 870 | 870 | 800 + 70 + 0 | Eight hundred seventy |
Key terms
- Standard form
- Writing a number the normal way: 347
- Word form
- Writing a number in words: three hundred forty-seven
- Expanded form
- Showing each digit's value: 300 + 40 + 7
- Three-digit number
- A number from 100 to 999 with hundreds, tens, and ones
Flashcards
- What is standard form?
- The normal way to write a number (e.g., 473)
- What is expanded form?
- Breaking a number into hundreds + tens + ones (e.g., 400 + 70 + 3)
- What is word form?
- Writing a number in words (e.g., 'four hundred seventy-three')
- What is the range of three-digit numbers?
- 100 to 999
- Write 852 in expanded form
- 800 + 50 + 2
- Write 300 + 60 + 1 in standard form
- 361
Practice questions
What is the standard form of 600 + 50 + 3?
- 365
- 653
- 635
- 563
Show answer
Answer: 653
600 + 50 + 3 = 653.
700 + 20 + 9 written in standard form is ___.
Show answer
Answer: 729
700 + 20 + 9 = 729.
The word form of 415 is 'four hundred fifteen.'
Show answer
Answer: True
415 = four hundreds + one ten + five ones = four hundred fifteen.
In the number 639, what is the value of the 3?
- 3
- 30
- 300
- 63
Show answer
Answer: 30
In 639, the 3 is in the tens place, so its value is 30.
Which number is in the correct order from least to greatest?
- 512, 521, 215
- 215, 512, 521
- 521, 512, 215
- 521, 215, 512
Show answer
Answer: 215, 512, 521
215 < 512 (hundreds 2 < 5); 512 < 521 (tens 1 < 2).
Fun facts
- The largest three-digit number is 999, and the smallest is 100.
- Three-digit numbers have been used for over 1,000 years to count everything from armies to grain in ancient civilizations!
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