Mental multiplication in 3 seconds

My 7th grade math teacher taught me the trick for the square of numbers ending in 5, which I had opportunity to use on various occasions, including on my SATs, but I had not known about the trick for the other complementary numbers until today.(almost 50 years later). Better late than never. Thanks!

I'm an old guy with memory issues. These tricks of yours are excellent exercises for me. Greatly appreciated.

You know I love dipping my toe into your lessons . I have to say though I think I have a fear of maths every time I look at your lessons my heartbeat goes crazy.

Hi there! I didn't get your way easily & would struggle to remember the rule But this is an older way of doing it & feels easier to remember, as you just round the big numbers up on one side & down on other side to nearest even number & so make them simpler to multiply in the tens & hundreds column & then just multiply the units as done in video . 63 x67 = 4221 same as 60 x 70 =4200 plus 3x7 =21 Total 4221 21 x 29 = 609 same as 20 x 30 = 600 plus 1x9 =9 Total 609 114 x 116 = 13,224 same as 110 x 120 = 13,200 plus 4 x 6 = 24 Total = 13,224 etc 45 to power of 2 45 x 45 = 2025 same as 40 x 50 = 2000 plus 5 x 5 = 25 Total = 2025

I try round one the numbers up or down to the nearest 10 and adjust after that. E.g. For 21 x 29; I do 21 x 30 = 630, then deduct 21 = 609 Or Sometimes I break it into 2 simpler calcs, E.g. For 21 x 29; I do 20 x 29 = 580, then 1 x 29 = 29; Then add the 2 = 609

Excellent trick...rare set of circumstances allow it, but great when the tens digits match and the ones digits add to ten. Thanks for sharing all you share.

Hmm...is it easier to remember these “tricks” or remember where I put my calculator.🤔

I living in India am learning western math And this guy is teaching me vedic math

“before you blast away in the comments...” No no no, that's what drives the algorithm!😁

Wow what a great maths teaching . I have got full marks in maths for this teaching 😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮😮.

Excellent content! Such a great explanation! Great work sir!

Me: bored Youtube: Want to learn some cool math from Bruce in Finding nemo? Me: Sure, why not.

I’m pushing 70 and I think these tricks are great! However, the one drawback is that the student doesn’t really understand WHY they’re arriving at the answer. That’s where doing the long version explains HOW you arrive at the answer. For instance, why do you multiply the 10s unit by 7? Saying that you increase the 10s place by 1 then multiply the 2 numbers needs further explanation. Do you get what I’m saying? When you’re first learning math, you need to understand the WHY and the HOW of the computation.

0:11 "I am gonna give you 3 seconds." Actually gives us 6 instead of 3. Imagine if the teacher did the same during the examinations.

What a great trick! In the 80s/90s, at least in my classes, we were drilled daily on our multiplication tables

Awesome way to work out multiplication of big numbers, wish we were taught this method at school and I would have enjoyed maths so much more, thankyou !

Thanks that’s a good one. I really like how fast we get the squared answer.

I love being able to use tricks to do basic math faster than most people can type it into a calculator. I’m definitely going to practice this one more and add it to my mental box of tricks. Great job.

Excellent‼️ Every little bit helps. 🤙🏽

It works because if b+c = 10, then (10a + b)*(10a + c) = 100a(a+1) + bc.