Adding Hundreds
Learn
In Grade 1, you learned to add numbers up to 100. Now you are ready to add bigger numbers - up to 1,000!
What Are Hundreds?
Hundreds are groups of 100. When we write 100, 200, 300, 400, 500, 600, 700, 800, or 900, we are counting hundreds.
Think of hundreds like big bundles. If you had 100 stickers in one pack, then 3 packs would be 300 stickers!
Adding Hundreds Is Like Adding Ones!
Here is a great secret: Adding hundreds works just like adding ones!
- 2 + 3 = 5, so 200 + 300 = 500
- 4 + 1 = 5, so 400 + 100 = 500
- 5 + 4 = 9, so 500 + 400 = 900
Just add the first digits and put two zeros after!
Using Place Value to Add
Remember place value? In the number 300:
- The 3 is in the hundreds place
- The 0 is in the tens place
- The other 0 is in the ones place
When we add 300 + 200, we add 3 hundreds + 2 hundreds = 5 hundreds = 500!
Worked Examples
Example 1: 100 + 200
Problem: Add 100 + 200
Step 1: Think about what we are adding: 1 hundred + 2 hundreds
Step 2: Add the hundreds: 1 + 2 = 3
Step 3: Write the answer with two zeros: 300
Answer: 100 + 200 = 300
Example 2: 400 + 300
Problem: Add 400 + 300
Step 1: Think: 4 hundreds + 3 hundreds
Step 2: Add: 4 + 3 = 7
Step 3: Answer: 700
Answer: 400 + 300 = 700
Example 3: 500 + 400
Problem: Add 500 + 400
Step 1: Think: 5 hundreds + 4 hundreds
Step 2: Add: 5 + 4 = 9
Step 3: Answer: 900
Answer: 500 + 400 = 900
Example 4: Word Problem
Problem: A library has 200 picture books and 300 chapter books. How many books does the library have in all?
Step 1: Find what to add: 200 picture books + 300 chapter books
Step 2: Add: 2 hundreds + 3 hundreds = 5 hundreds
Step 3: Write the answer: 500
Answer: The library has 500 books in all.
Example 5: Adding Three Numbers
Problem: Add 100 + 200 + 400
Step 1: First add 100 + 200 = 300
Step 2: Then add 300 + 400 = 700
Answer: 100 + 200 + 400 = 700
Practice Problems
Try these problems on your own. Click "Show Answer" to check your work!
Problem 1: 100 + 100 = ?
Show Answer
200 (1 hundred + 1 hundred = 2 hundreds)
Problem 2: 200 + 300 = ?
Show Answer
500 (2 hundreds + 3 hundreds = 5 hundreds)
Problem 3: 300 + 400 = ?
Show Answer
700 (3 + 4 = 7, so 300 + 400 = 700)
Problem 4: 600 + 200 = ?
Show Answer
800 (6 + 2 = 8, so the answer is 800)
Problem 5: 100 + 800 = ?
Show Answer
900 (1 + 8 = 9, so the answer is 900)
Problem 6: 400 + 400 = ?
Show Answer
800 (4 + 4 = 8, so the answer is 800)
Problem 7: A farmer has 300 apples. She picks 200 more. How many apples does she have now?
Show Answer
500 apples (300 + 200 = 500)
Problem 8: 500 + 300 = ?
Show Answer
800 (5 + 3 = 8, so the answer is 800)
Problem 9: A school has 400 boys and 500 girls. How many students are there?
Show Answer
900 students (400 + 500 = 900)
Problem 10: 100 + 300 + 200 = ?
Show Answer
600 (1 + 3 + 2 = 6, so the answer is 600)
Check Your Understanding
Question 1: When adding 300 + 500, what do you add first?
Show Answer
You add the hundreds digits: 3 + 5 = 8, then write 800.
Question 2: Why is adding hundreds like adding ones?
Show Answer
Because you just add the digits in the hundreds place, like adding single numbers. 2 + 3 = 5 is the same idea as 200 + 300 = 500!
Question 3: What is 200 + 700?
Show Answer
900 (2 + 7 = 9, so 200 + 700 = 900)
Question 4: Can you add 600 + 500? What happens?
Show Answer
600 + 500 = 1,100. When you add and get more than 9 hundreds, you get into the thousands! This is a preview of what you will learn next.
Next Steps
- Practice: Try making up your own addition problems with hundreds
- Challenge: Can you add hundreds in your head without writing them down?
- Next Lesson: Learn to subtract hundreds in the next lesson!
- Real Life: Look for big numbers in books, on signs, or in stores