**Elementary School Number Sense Lesson 9: Multiplying Whole Numbers (3 or More)**

Today's lesson is an "oldie but a goodie"--and it builds upon our

**MultWhole**skills. It has appeared

**5 times**so far this year, with a median placement at

**question # 9**.

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To solve these problems the most quickly and accurately, it may be best to rearrange their order (and not multiply left-to-right as they are presented). I will show you several examples of how I approach the order of multiplication, depending on the factors being multiplied.

**Example 1: 9 x 10 x 11 = ___**

- As soon as I see a
**10**in these problems, I write down a**0**(to be the last part of the answer). - We are left with
**9 x 11**, which is**99**; write this in front. The answer is**990**.

**Example 2: 6 x 4 x 2 x 0 = ___**

- Notice the
**0**at the end of the problem. Anything times 0 is**0**. - The answer is
**0**.*Don't waste your time multiplying 6 x 4 x 2 first!*

**Example 3: 8 x 7 x 5 = ___**

- Whenever there is a factor of
**5**, I try to pair it up with an even number and basically**Double/Half**it. 8 x 5 =**40**. - 40 x 7 =
**280**.

**Example 4: 9 x 5 x 4 = ___**

- Multiply
**5 x 4**first, which is**20**. - 9 x 20 =
**180**.

**Example 5: 12 x 6 x 12 = ___**

- There is no super-easy way to approach this one. I would probably go left-to-right: 12 x 6 =
**72**. - Using
**Mult12**, 72 x 12 = 72 x (10 + 2) = (72 x 10) + (72 x 2) = 720 + 144 =**864**.

**Here's a free worksheet to help you practice MultWhole3Num:**

multwhole3num.pdf |

**Up Next for Elementary School: PlaceValue**