multiplying any number with 12

 

We have seen this tutorial, how to multiply any number  with 11.  In this tutorial, we will see, how to multiply any number with 12.

We are going to learn 2 shortcuts here. I will explain both. You can practice whichever technique you feel is easier.

Let me consider a very simple example. Let‘s say, we want to multiply 34*12.

In the first approach, we use the technique we already know. We already know how to multiply any number with 11. We can write 34*12 as,

34*12 = 34*(11+1) = 34*11 +34

 multiplication_12

So, 34*12 = 374+34 = 408.

 

Let’s consider another example. Let’s say we need to multiply 652*12. We can write,

652*12 = 652*(11+1) = 652*11 +652

 multiplication_12_2

So, 652*12 = 7172+652= 7824.

Using this technique, can you multiply?

  • 34567 x 12
  • 234 x12
  • 59403 x 12
  • 393933 x 12

 

Now, let’s try to understand the second technique. Let’s consider the same example 34*12.

 multiplication_12_3

 

The idea is to double every digit and add it to its neighbor.

Step 1:  Starting from right, double the right most digit 4, that is 8.

Step 2: Now, double the next digit 3 and add it to 4 to get 10. Write 0 and 1 is carry-forward.

Step 3: In the last step, we do not  double the digit. So, 3 is added to the previous carry-over to get 4.

So, the final answer is 408.

 

Let’s take another example 652*12

multiplication_12_4

 

Step 1:  Starting from right, we double the right most digit, so we have 4*2 =8.

Step 2:  Starting from right, we double the next digit and add the previous digit 2. So, we get 5*2+2=12.

Step 3:  We double the last digit 6 and add the previous digit 5. So, we get 6*2+5=17. We have the carry-forward from the previous addition as well. So we get 18.

Step 4: In the last step, we do not double the digit. So, 6 is added to the previous carry-over 1 to get 7.

So, the final answer is 7824.

 

Using this technique, can you multiply?

  • 34567 x 12
  • 234 x 12
  • 59403 x 12
  • 393933 x 12

 

Very easy right 🙂

Please leave a message if some point in this tutorial is not clear to you. I would be glad to help.

 

 

Kiran Chandrashekhar

Hey, Thanks for dropping by. My name is Kiran Chandrashekhar. I am a full-time software freelancer. I love Maths and Mathematical Shortcuts. Numbers fascinate me. I will be posting articles on Mathematical Shortcuts, Software Tips, Programming Tips in this website. I love teaching students preparing for various competitive examinations. Read my complete story.

3 Comments

  1. In the topic “multiplying any number with 12” there is a typo,
    34*11 = 374 (not 372)
    So, 34*12 = 374+34 = 408.

    Please correct it.

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