3-digit addition and subtraction — Maths worksheet

The method

Column by column — “work from the ones to the hundreds, carrying or borrowing one at a time”

1. Line up ones, tens and hundreds.
2. Add from the right; 10 or more → carry 1 to the next column.
3. Subtract from the right; top digit smaller → borrow 1 from the next column.
4. Missing number in an addition = total − the number you know.

Use it for: Passengers on trains, children in a school, and the addition and subtraction chapters of Class 3 maths.

Worked example: 456 + 378 = 834

✏️ Practice

Work it out in your head or on paper, then tap your answer — or type it and press Check. Stuck? Press “Show me how”.

🏁 Lesson 17 test

20 sums. Check each answer, then go to the next one. Get 16 or more right to pass.

🏅 Sign in with Google to earn the 🧮 Three-Digit Tamer badge when you pass — and a certificate when you finish all 8 lessons of Part 3 · Class 3. You can still take the test without signing in.

🖨️ Class 3 Maths Worksheet: Addition and Subtraction

• Worksheet set 1 (PDF)
• Worksheet set 2 (PDF)
• Worksheet set 3 (PDF)