How To Multiply Any Number by 11 Mentally

This is a guide on how to easily multiply any number by 11 mentally and without the aid of a calculator. It can be a cool party trick or maybe you just need to multiply by 11 in a pinch. You never know, maybe after learning this trick the ladies(gents, whatever you're in to) will come flocking....or not.

Step 1 Limitations and Precautions

There is no real limit to what number you can multiply by 11 with this trick. Just be aware that as you move into larger numbers, they become a little more time intensive. The only background I would suggest to have in this trick is be really familiar with your basic addition tables and be quick. The quicker you are with simple addition, the quicker this trick goes.

Comments

[admin]

Hey, this is a great instructable and is very informative. Just one thing is missing... pictures! It really helps a lot when trying to follow directions so you should consider taking some photographs. Once you do that and leave me a message when you have so that we can publish your work. Thanks! Thanks for the cool instructable and we hope to publish this soon!

[tristinGrind]

Pictures added!

[Spypro]

very nice :)

[macmaniac]

It's not doing it mentally if you have to write stuff down

[tristinGrind]

I only tell you to write it down in the beginning to show you how it works. I dont write anything down as Ive been doing if for quite some time now. Its the same as when youre a kid... you write everything out, but as you get better you can do it all in your head; same concept.

[R0B0_Ninja]

Very well explained. Simple, yet fascinating stuff like this could make more people be interested in math.

[Barney Watches You]

cool thanks