**Middle School Number Sense Lesson 25: Multiplying Two Numbers Just below 100**

This skill works the same way as

**Mult101-109**, but with a little twist. It appeared

**12 times**this year in middle school (in other words, on

**80%**of the tests), most often at

**question # 22**.

**Number Dojo Level: 114**

Just like in

**Mult101-109**, imagine each number is made up of two parts:

- 100
- A small number subtracted from the 100

**How to Solve:**

- Think: "How far below 100 are each of these numbers?" In other words, subtract each number from 100 to get 2
**differences**. - Multiply those 2 differences together and write their product down as 2 digits. (If their product exceeds two digits, write the last 2 digits and regroup the first).
- Subtract the 2nd difference from the first original number (and add any regrouping), and write this result in front of the product from step 2.

**Example 1: 97 x 92**

- Subtract each number from 100. 100 - 97 =
**3**, and 100 - 92 =**8**. - Multiply these differences.
**3**x**8**=**24**; write this down. - Subtract the 2nd difference from the first original number, and write this in front.
**97 - 8 = 89**. The answer is**8924**.

**Example 2: 94 x 98**

- Subtract each number from 100. 100 - 94 =
**6**, and 100 - 98 =**2**. - Multiply these differences.
**6**x**2**=**12**; write this down. - Take the first number (
**94**) minus the 2nd difference (**2**).**94 - 2 =****92**; write this in front. The answer is**9212**.

**Example 3: 99 x 93**

- Subtract each number from 100. 100 - 99 =
**1**, and 100 - 93 =**7**. - Multiply these differences.
**1 x 7 = 7**; write down**07**. - Take
**99 - 7**to get**92**; write this in front. The answer is**9207**.

**Example 4: 89 x 95**

- Subtract each from 100. 100 - 89 =
**11**and 100 - 95 =**5**. - Multiply these differences.
**11 x 5 = 55**; write this down. - Take
**89 - 5**to get**84**; write this in front. The answer is**8455**.

**Example 5: 91 x 88**

- Subtract each from 100. 100 - 91 =
**9**and 100 - 88 =**12**. - Multiply these differences.
**9 x 12 = 108**. Write down**08**and**regroup the 1**. - Take
**91 - 12**to get**79**, plus the**regrouped 1**to get**80**. Write this in front. The answer is**8008**.

**Here's a free worksheet to help you practice Mult90-99:**

mult90-99.pdf |

**And a video.**

Up Next for Middle School: FindGCF

Up Next for Middle School: FindGCF