Multiplication — Grade 4 Mathematics
In Grade 4, we learn long multiplication for 2-digit × 2-digit calculations, use the expanded grid method to understand the process, and confidently multiply 3-digit numbers by 1-digit numbers. We also multiply by multiples of 10 and 100.
Grid Method: 2-Digit × 2-Digit
To multiply 34 × 27, partition both numbers:
34 = 30 + 4 | 27 = 20 + 7
Make a 2×2 grid and multiply each pair.
34 = 30 + 4 | 27 = 20 + 7
Make a 2×2 grid and multiply each pair.
×
30
4
20
600
80
7
210
28
600 + 80 + 210 + 28 = 918
Long Multiplication Method
Written method for 34 × 27:
1. Multiply 34 by 7 (ones) → 238
2. Multiply 34 by 20 (tens) → 680 (write a 0 placeholder)
3. Add the two partial products: 238 + 680 = 918
1. Multiply 34 by 7 (ones) → 238
2. Multiply 34 by 20 (tens) → 680 (write a 0 placeholder)
3. Add the two partial products: 238 + 680 = 918
H T O
3 4
× 2 7
2 3 8 ← 34 × 7
6 8 0 ← 34 × 20
9 1 8
× 2 7
2 3 8 ← 34 × 7
6 8 0 ← 34 × 20
9 1 8
Worked Examples
Example 1 — Long Multiplication
Calculate 56 × 43
- 56 × 3 = 168
- 56 × 40 = 2 240
- 168 + 2 240 = 2 408
Example 2 — Multiply by 30, 200, 400
Calculate: (a) 47 × 30 (b) 62 × 200
- (a) 47 × 3 = 141; then × 10 → 1 410
- (b) 62 × 2 = 124; then × 100 → 12 400
Example 3 — Real World: Concert Tickets 🎵
A concert sells 48 tickets for each of 36 performances. How many tickets in total?
- 48 × 36 = 48 × 30 + 48 × 6
- = 1 440 + 288 = 1 728 tickets
Practice Questions
1. Calculate 35 × 24.
✅ 35×4=140; 35×20=700; 140+700=840
2. Calculate 67 × 58.
✅ 67×8=536; 67×50=3 350; 536+3 350=3 886
3. What is 85 × 300?
✅ 85 × 3 = 255; × 100 = 25 500
4. A box holds 24 cans. How many cans in 75 boxes?
✅ 24×75 = 24×70+24×5 = 1 680+120 = 1 800 cans
5. Calculate 124 × 7.
✅ 100×7=700; 24×7=168; 700+168=868
Key Points to Remember
- Long multiplication: multiply by ones first, then tens (add a 0 placeholder), then add.
- Grid method: partition both numbers into tens and ones, multiply each pair, add all four products.
- × 10: add one zero. × 100: add two zeros. × 30 = × 3 then × 10.
- Estimate first: 56 × 43 ≈ 60 × 40 = 2 400 (actual: 2 408 ✓).
- Multiplication is commutative: 56 × 43 = 43 × 56.