Video : Multiplication of 2 numbers whose last digit adds to 10


This shortcut is applicable when you have to multiply two 2-digit numbers having the same first digit and the unit digits add to 10. For example : 72 x 78, 81 x 89 etc.


This is an extension of the mathematical shortcut, how to obtain the square of a number ending in 5.  There is already an article which explains this shortcut. You can read about this shortcut here.

The following video tutorial explains this mathematical shortcut, how to multiply such numbers.

 

 

The entire steps can be illustrated with the following figure as well.

 

multiply_add_10_5

 

Using this shortcut, can you multiply :

  • 24 x 26
  • 22 x 28
  • 91 x 99
  • 112 x 118

I hope you find this tutorial useful. If you have any doubts with this tutorial, please leave a comment or contact me, 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.

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