Multiplication and Division: Class 4 Study Guide
Multiplication and division are inverse operations. Tables up to 10 make both fast.
To multiply a larger number by a single digit, multiply each place from the right, carrying when needed. For 246 × 3: 6 × 3 = 18, write 8 and carry 1; 4 × 3 = 12 + 1 = 13, write 3 and carry 1; 2 × 3 = 6 + 1 = 7. The answer is 738.
Division is sharing equally or grouping. In long division we divide, multiply, subtract and bring down. If something is left over, it is the remainder, which must be smaller than the divisor.
Multiplying step by step
246 on top, 3 below.
6 × 3 = 18. Write 8, carry 1.
4 × 3 = 12, plus 1 = 13. Write 3, carry 1.
2 × 3 = 6, plus 1 = 7. Answer: 738.
Long division
To divide 85 by 4: 4 goes into 8 twice (2), 2 × 4 = 8, subtract to get 0, bring down 5. 4 goes into 5 once, 1 × 4 = 4, remainder 1. So 85 ÷ 4 = 21 remainder 1. Check by multiplying: 21 × 4 + 1 = 85.
| Step | What to do | For 85 ÷ 4 |
|---|---|---|
| Divide | How many times does 4 go into 8? | 2 |
| Multiply | 2 × 4 | 8 |
| Subtract | 8 − 8 | 0 |
| Bring down | Bring down the 5 | 05 |
| Repeat | 4 into 5 once, remainder 1 | 21 R 1 |
Word problems
Look for clue words. Each, per, every, times usually mean multiply. Share equally, divide, how many groups mean divide. Example: A box holds 24 pencils. How many pencils are in 15 boxes? 24 × 15 = 360. Another: 125 laddoos are packed in boxes of 8. How many boxes are full, and how many laddoos are left? 125 ÷ 8 = 15 remainder 5.
Worked examples and common mistakes
Example: 128 × 4 = 512. Example: 97 ÷ 5 = 19 R 2. Common mistakes: forgetting to add the carried number, ignoring the remainder in a word problem and not lining up digits. Estimate first: 128 × 4 is about 100 × 4 + 28 × 4 = 512.
Check your understanding: model answers
1. 1,268. 2. 15 remainder 2. 3. 12 × 25 = 300 pens.
✨ Key Takeaways
- Multiply each place from the right, carrying when needed.
- Long division: divide, multiply, subtract, bring down.
- A remainder is smaller than the divisor.
- Check by the inverse operation.
💬 Questions for Discussion & Reflection
- Find 317 × 4.
- Find 92 ÷ 6 with the remainder.
- A shop sells 12 pens per packet. How many pens in 25 packets?