Mathematics -- Class 3

Topic: Addition and Subtraction Practice (3-Digit Numbers)
Name: ____________________________Class: 3Date: ________________
Learning Objectives
Let Us Begin!

Meena's school collected 347 books in the first week and 285 books in the second week for a book donation drive. How many books were collected in all? To find out, we add the two numbers.

Sometimes when we add, the total in a column is more than 9. Then we carry the extra to the next column. This is called regrouping.

If the school gave away 268 books from a stock of 503, how many are left? We subtract. Sometimes the top digit is smaller, so we borrow from the next column.

Step-by-Step: Addition with Carrying

Example: 347 + 285

HTO
347
+285
=632

Step 1 (Ones): 7 + 5 = 12. Write 2 in the Ones column. Carry 1 to the Tens column.

Step 2 (Tens): 4 + 8 = 12, plus the carried 1 = 13. Write 3 in the Tens column. Carry 1 to the Hundreds column.

Step 3 (Hundreds): 3 + 2 = 5, plus the carried 1 = 6. Write 6 in the Hundreds column.

Answer: 347 + 285 = 632

Step-by-Step: Subtraction with Borrowing

Example: 503 - 268

HTO
503
−268
=235

Step 1 (Ones): 3 − 8? We cannot! Borrow 1 ten from the Tens column. But Tens column is 0, so borrow 1 hundred from the Hundreds column first. H becomes 4, T becomes 10. Now borrow 1 ten for Ones: T becomes 9, O becomes 13. Now 13 − 8 = 5.

Step 2 (Tens): 9 − 6 = 3.

Step 3 (Hundreds): 4 − 2 = 2.

Answer: 503 − 268 = 235

Checking Subtraction Using Addition

Think: If 503 − 268 = 235, then 235 + 268 should give us back 503. Let us check: 235 + 268 = 503. Correct!

Rule: Difference + Smaller Number = Bigger Number. If this is true, your subtraction is correct.

Key Words and Meanings
WordMeaning
Carrying (Regrouping)When the sum in a column is 10 or more, we write the ones digit and carry the tens digit to the next column
Borrowing (Regrouping)When the top digit is smaller, we take 1 from the next column to make it bigger
SumThe answer we get after adding
DifferenceThe answer we get after subtracting
Place ValueThe value of a digit based on its position (Ones, Tens, Hundreds)
Quick Example: Addition

456 + 378: Ones: 6+8=14, write 4 carry 1. Tens: 5+7=12+1=13, write 3 carry 1. Hundreds: 4+3=7+1=8. Answer: 834.

Quick Example: Subtraction

700 − 356: Borrow step by step. O: 10−6=4, T: 9−5=4, H: 6−3=3. Answer: 344.

Mathematics -- Class 3 (continued)

Topic: Addition and Subtraction -- Practice
Practice Sums -- Solve in Vertical (Column) Format

A. Addition (with carrying)

  1. 256 + 478 =
  2. 389 + 245 =
  3. 167 + 558 =
  4. 493 + 327 =
  5. 275 + 486 =
  6. 648 + 197 =
  7. 534 + 289 =
  8. 176 + 465 =

B. Subtraction (with borrowing)

  1. 612 − 347 =
  2. 800 − 456 =
  3. 503 − 179 =
  4. 741 − 368 =
  5. 920 − 584 =
  6. 405 − 238 =
  7. 600 − 273 =
  8. 532 − 467 =
Key Points to Remember
Word Problems
  1. A fruit seller had 465 mangoes. He sold 278 mangoes. How many mangoes are left?
  2. Ravi's school has 384 boys and 279 girls. What is the total number of students in the school?
  3. A train had 510 passengers. At the next station, 186 passengers got down. How many passengers are still on the train?
  4. Anita collected 247 stamps in January and 385 stamps in February. How many stamps did she collect in all?
  5. A shopkeeper had 900 packets of biscuits. He sold 567 packets. How many packets are left? Check your answer using addition.
Think and Do -- Fun Activity

Number Detective: Solve each subtraction below. Then check your answer by adding the difference to the smaller number. Write "Correct" or "Try Again" next to each.

1. 704 − 389 = _________   Check: _________ + 389 = _________

2. 561 − 275 = _________   Check: _________ + 275 = _________

3. 830 − 462 = _________   Check: _________ + 462 = _________

Challenge: Write your own 3-digit addition sum where carrying happens in all three columns. Solve it and ask a friend to check!

My sum: _________ + _________ = _________