**Elementary School Number Sense Lesson 26: Multiplying by 15**

These problems can be solved using

**Double/Half**or

**Mult12-19**, but I prefer a different method. This concept appeared

**4 times**this year, with a median placement at

**question # 19**.

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When multiplying by 15, we can use the distributive property and split it into

**10 and 5**. I basically solve them this way, but with a twist…

**How to Solve:**

- Divide the number by 2
- Add the result to the original number
- Multiply by 10

**Example 1: 18 x 15 = ___**

- Divide 18 by 2 to get
**9** - Add 9 to 18 to get
**27** - Multiply by 10 (add a 0):
**270**

**Example 2: 15 x 24 = ___**

- Divide 24 by 2 to get
**12** - Add 12 to 24 to get
**36** - Multiply by 10 (add a 0):
**360**

**Example 3: 64 x 15 = ___**

- Divide 64 by 2 to get
**32** - Add 32 to 64 to get
**96** - Multiply by 10:
**960**

**Example 4: 15 x 84 = ___**

- Divide 84 by 2 to get
**42** - Add 42 to 84 to get
**126** - Multiply by 10:
**1260**

**Example 5: 124 x 15 = ___**

- Divide 124 by 2 to get
**62** - Add 62 to 124 to get
**186** - Multiply by 10:
**1860**

**Here's a free worksheet to help you practice Mult15:**

mult15.pdf |

**Up Next for Elementary School: Mult101**