Decimal Multiplication Worksheet 5th Grade - Free Printable

It looks like you've uploaded an image of a math worksheet titled "Double Digit Multiplication (10 to 19 times 10 to 19)". The task is to multiply each pair of two-digit numbers, where both numbers range from 10 to 19.

Let me solve all the problems and explain the method clearly.

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🔢 Instructions:

Multiply the two numbers in each problem using standard multiplication techniques or mental math strategies.

We'll go through each one step by step.

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✔ Solutions:

#### 1) 12 × 13
= (10 + 2)(10 + 3) = 10×10 + 10×3 + 2×10 + 2×3 = 100 + 30 + 20 + 6 = 156

#### 2) 12 × 14
= 12×(10+4) = 120 + 48 = 168

#### 3) 14 × 16
= (10+4)(10+6) = 100 + 60 + 40 + 24 = 224

#### 4) 13 × 17
= (10+3)(10+7) = 100 + 70 + 30 + 21 = 221

#### 5) 14 × 17
= 14×10 + 14×7 = 140 + 98 = 238

#### 6) 15 × 14
= 15×(10+4) = 150 + 60 = 210

#### 7) 15 × 15
= 225 → This is a perfect square: 225

#### 8) 16 × 15
= 16×(10+5) = 160 + 80 = 240

#### 9) 17 × 15
= 17×10 + 17×5 = 170 + 85 = 255

#### 10) 18 × 16
= 18×(10+6) = 180 + 108 = 288

#### 11) 18 × 14
= 18×(10+4) = 180 + 72 = 252

#### 12) 17 × 16
= (10+7)(10+6) = 100 + 60 + 70 + 42 = 272

#### 13) 18 × 18
= (18)^2 = 324 → 324

#### 14) 19 × 17
= 19×(10+7) = 190 + 133 = 323

#### 15) 19 × 15
= 19×(10+5) = 190 + 95 = 285

#### 16) 19 × 16
= 19×(10+6) = 190 + 114 = 304

#### 17) 19 × 18
= 19×(10+8) = 190 + 152 = 342

#### 18) 19 × 19
= (19)^2 = 361 → 361

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📋 Final Answers:

| Problem | Answer |
|--------|--------|
| 1) 12 × 13 | 156 |
| 2) 12 × 14 | 168 |
| 3) 14 × 16 | 224 |
| 4) 13 × 17 | 221 |
| 5) 14 × 17 | 238 |
| 6) 15 × 14 | 210 |
| 7) 15 × 15 | 225 |
| 8) 16 × 15 | 240 |
| 9) 17 × 15 | 255 |
| 10) 18 × 16 | 288 |
| 11) 18 × 14 | 252 |
| 12) 17 × 16 | 272 |
| 13) 18 × 18 | 324 |
| 14) 19 × 17 | 323 |
| 15) 19 × 15 | 285 |
| 16) 19 × 16 | 304 |
| 17) 19 × 18 | 342 |
| 18) 19 × 19 | 361 |

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💡 Explanation & Tips:

- These are all double-digit multiplications, but since they're between 10–19, we can use:
- Distributive property: e.g., 14 × 16 = (10 + 4)(10 + 6)
- Break into parts: Multiply tens and ones separately.
- Use known squares: Like 15² = 225, 18² = 324, 19² = 361.

- You can also use standard multiplication algorithm (column method), but for speed, breaking down helps.

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✔ All answers have been calculated accurately.

Let me know if you'd like a printable version or a PDF of the solutions!