**Middle School Number Sense Lesson 14: Multiplying by 125 (and variation)**

This concept is an extension of Mult50 and Mult25. (If you haven't spent any time on those two concepts, it would be a good idea to review them now by clicking their hyperlink).

The number 125 happens to be exactly 1/8 of 1000. You can probably figure out how to handle these types of problems without much instruction. This variation has a bit of a twist. It showed up

**6 times**this year, usually at around

**question # 15**.

**Number Dojo Levels: 91, 125**

**To multiply any number by 125:**

- Divide it by 8.
- Multiply by 1000. You're done.

**Example 1: 56 x 125**

- Divide by 8. 56 ÷ 8 =
**7**. - Multiply by 1000. 7 x 1000 =
**7000**.

**Example 2: 125 x 128**

- Divide by 8. 128 ÷ 8 =
**16**. - Multiply by 1000. 16 x 1000 =
**16000**.

**Variations:**

- Sometimes the number you're multiplying by 125 is a decimal or fraction. Instead of simply adding 3 zeros, you need to be careful with moving the decimal 3 places.
- Other times, you are asked to multiply by 12.5 or 12 1/2. In these cases, you will multiply by 100 instead of 1000 because 12.5 is
**1/8 of 100**. - Sometimes, both numbers will be decimals or fractions. Be extra careful with the decimal places on these.

**Example 3: 125 x 0.88**

- Divide by 8. 0.88 ÷ 8 =
**0.11** - Multiply by 1000. 0.11 x 1000 =
**110**.

**Example 4: 12 1/2 x 32**

- Divide by 8. 32 ÷ 8 =
**4**. - Multiply by 100. 4 x 100 =
**400**.

**Example 5: 1.6 x 12.5**

- Divide by 8. 1.6 ÷ 8 =
**0.2**. - Multiply by 100. 0.2 x 100 =
**20**.

**Here's a free worksheet to help you practice Mult125var:**

mult125var.pdf |

**And a video.**

Up Next for Middle School: Square11-20

Up Next for Middle School: Square11-20