Multiplication Math Hack for 2-Digit Numbers Ending in 1 (Mental Math Trick) #shorts #math #maths

[allope]

It feels like the long way with all these tricks 😂 if you're new to them and try to remember all the trick it will only confuse you but after years finally it will help

[OLF-lotr]

This was how I was taught to do double digit multiplication.
The order is lasts, innies + outties, then firsts.
Ex: 61×31,
Step 1. Lasts, 1×1 = 1
Step 2. Innies + outties, 3×1 + 6×1 = 9
Step 3. Firsts, 6×3 = 18
Step 4. Figuring out where the numbers go, 1, 9, 18, the 1 goes last, the 9 goes next to the 1(any number over 10 you carry the tens digit to the next number in the sequence, ) the 18 goes first so the answer is 1891.
While yes this one is easy this sequence works for all 2 digit by 2 digit multiplication and can be adapted for 3 digit multiplication as well.
Ex2: 78×34
8×4 = 32
8×3 = 24. 7×4 = 28. 24+28 = 52
7×3 = 21
32 is first so the 2 is the ones digit, carry the 3. 52 is next, add the 3 from before to get 55. So 5 is the tens digit, carry a 5. 21 is last add the 5 to get 26, so a 6 is the hundreds digit the 2 is alone so no need to carry and it becomes the thousands digit.
So 78×34 = 2652.

I want to see how many people can get this one right.
85×47.

If you want more math tips I know a few.

[PGCTalha]

I would've done 61x30 then added 61 to the answer which is easier for me

[ACheateryearsago]

Just do 61×30+61×1
Now just multiply 61×3 then add a 0 at the end..
3(60+1)
=180+3
=183
With a 0 at the end, it will become 1830..
Finally, add 61×1
1830+(61×1)
=1830+61
=1891

Much simpler!

[JusticeShepard]

This trick works 100% of the time. If the first digits add up to 10 or more, you carry the 1 👍🏼

[-_-.]

For the people say this is not true lets say a and b are positive integers a1 and b2 are 2 digit numbers so a1×b1=(10a+1)×(10b+1)
=100ab+10(a+b)+1
So in this case first or second digits are ab or ab+1 (if a+b>=10) after that the digit is a+b or a+b-10 (if a+b>=0) and the last digit is 1 in conclusion
If a+b<10, ab<10
---> first is a×b second digit is a+b third digit is 1
If a+b<10, ab>=10
--->first and second digits are a×b third digit is a+b fourth digit is 1
If a+b>=10, ab<9
--->first digit is ab+1 second digit is a+b-10 third digit is 1
If a+b>=10, ab>=9
--->first and second digits are ab+1 third digit is a+b-10 fourth digit is 1

[harshit]

Ok that's formula just works for number ending one
But there's actually a way that works for every two digit multiplication
For two digit
Let assume two number ab and cd
Multiply ab
×CD

aD bD
+ aC bC. ×

aC (aD+bC) bD

That's our formula
Lets suppose 91×18
91=ab and 18=CD
Formula aC (aD+bC) bD
By formula
91
×18

(9×1) [(9×8)+(1×1)] (1×8)
9 73 8
And yeah imp to remember never the digit should be more than one digit
If it is then the digit other the unit place goes to carry to the left side number
So 73 is two digit 7 goes to carry to left i.e 9+7
(9+7)(3)(8)
1638 is ans
The left number can be more than 1 digit number but middle and right one can never be if they are just carry forward
Suppose after doing by formula the ans comes
(16)(9)(12)
Right one gives Carry to middle one
16 (9+1)(2)
16 (10) (2)
Now middle will also give carry
(16+1)(0)(2)
1702 will be the ans

It seems long but after practice multiplication becomes easy
Works for every two to two digit multiplication

There's also such formula for 3 digit multiplication and four digit multiplication

[simoneaux]

It’s commendable to be quick at solving a math problem. Who really gives a fuck if your answer’s wrong 50% of the time using this method

[bryanjohnson]

If you add 1 and one then divide multiply and subtract... then add to the first then divide by 2 then subtract 1 and multiply by 1. Then add by 2 subtract 1 divide by 1 then multiply by 2.... see the answer is so easy!

[elgato_carrys]

If its for eg: 81x91 when u add the 2 numbers it = 17 carry the 1 to the last step number so 72+1 = 73 and the answer is “7371” not “72️⃣71

[willmcgee]

Just teach the foil method which works for all multiplication

(60 + 1)(30 + 1)=1800+30±60±1

[ro-ok]

You made it even worse that the original multiplication

[Insomnia_Animations]

The thing is, you never explain why these things work, and that's the most important part!

[johngaltline]

It's a neat trick, but you can just do the multiplication just as fast.

[hodanmuse]

this literally just blows my mind. How did you do that whenever I try to check it never works I literally watch a video of 100 million times and I try but it doesn’t work and I don’t know how I don’t do that

[jarodmalaga]

Thank you bro that make me past on math test for that i will subscribe you

[onradioactivewaves]

So doing regular multiplication is a trick now? What a treat.

[bacillus]

Iykyk ...all these tricks are indian Vedic mathematics

[keanusabine]

Just multiply 61 by 3 which is 183, multiply by ten which is 1830, add it to 61 which 1891

[arikuchiri_]

I do 61×31 like 610+610+610+61. 610+610 or 610x2 would be equivalent 1220. Now we got 1220+610+61, 1220+610 would be equivalent to 1830, so now we just get 1830+61, which is extremely easy, it is 1891, so 61×31=1891.