top of page
Search
• Merry Havens

# Rapid Math Tricks Multiply by 11

Updated: Oct 25, 2019

We first learned how easy it is to multiply single digits by 11....easy: 2 x 11 is 22. 8 x 11 is 88.

But what do we do when we have 2 digit numbers to multiply by 11? Well, it turns out to be just as easy! 32 x 11 is 352 and 45 x 11 is 495....see a pattern here?

For 32 x 11, put the sum of 3 and 2 (5) between 3 and 2, and for 45 x 11, put the sum of 4 and 5 (9) between 4 and 5. So, let's try a couple:

1. 27 x 11 =

2. 34 x 11 =

3. 51 x 11 =

4. 63 x 11 =

5. 81 x 11 =

get it?

1. 297 the sum of 2 and 7 (9) between 2 and 7

2. 374 the sum of 3 and 4 (7) between 3 and 4

3. 561 the sum of 5 and 1 (6) between 5 and 1

4. 693 the sum of 6 and 3 (9) between 6 and 3

5. 891 the sum of 8 and 1 (9) between 8 and 1

Amaze your friends and family by showing them this trick.

What to do in the case where the 2 digits add up to more than 9? Just carry the 1.

For example: 39 x 11 is (3 + 9 in the middle 12...put down the 2 carry the 1 to the 3) so the answer is 429....easy, right?

## Recent Posts

See All

Solving Linear Equations

Linear equations come in many forms. Easy conversion between the different forms can come in very useful for solving linear equations and graphing. Slope Intercept form: y = mx + b where m is

Solving 2 variable equations

There are basically 2 types of 2-variable equations you will be asked to solve. The first type is asking, what is y when x is _____? For example, for the linear equation y = 3x + 4....what is y whe