UK - Math Olympiad Question | You should be able to solve this without calculators!!
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- Опубликовано: 30 сен 2024
- Maths Olympiads are held all around the world to recognise students who excel in maths. The test is offered at many grade levels and provides them with numerous possibilities to win certifications, awards, and even scholarships for higher studies.
I can’t imagine a more difficult and error-prone solution. How about (8x12)(11x9)x10. I can do this in my head. 96x99=9600-96=9504. Times 10=95040.
I've done the same thing
Nice! 👍
The same here
Same in 20 sec
I completely agree with you
For this calculation I will multiple them In a paper normally💖♥
That's the conclusion I came to. I looked at this as 12!/7!, factored the numerator and denominator (very easy), a lot of factors canceled, and I was left with multiplying 64*27*5*11, which can be simplified to 64*27*55. What did I save by doing this? NOTHING. I agree with you, just multiply the original numbers. The first three can be done in your head, 8*9*10 = 72*10 = 720, and even 720*11 can be done in your head (or at least almost), 720*11 = 7200+720. These attempts to make it easy actually make it harder!
That's the reason why you are not a genius 😂
What's the logic behind this? The more complicated, the easier it is?!
This is math Olympics and these are the original formats of this stuff when they were first coming up with all of this this is what actual math looks like and when they're trying to get high-ranking jobs and stuff like that this is the type of math format that they're looking for they don't want to see not one one times one
No. Simply use the third binomial formula (a + b) (a - b) = a² - b².
This way you get 8 ⋅ 12 = 96 and 9 ⋅ 11 = 99.
Now, 96 ⋅ 10 = 960 and 960 ⋅ 99 = 960 ⋅ 100 - 960 ⋅ 1 = 96.000 - 960 = 95.040.
Quick and easy.
isnt it easy to multiply them? I was thinking you will be using (x+y)(x-y)
Third binomial formula is the fastest way.
Worst method
Multiply 9*11= 99 and 8*12=96
Multiply 99 and 96 using Vedic method
9504
Multiply this with ten
Orally it can be done
You have pleased me .Your method is praiseworthy .❤❤❤
Brute force are helpful only in these easy questions. But the concept she explained is important and it will be used later in many questions. So it's better to find other solutions as well.
For 3 marks question you will write ✍️ full explanation properly. For 1 marks it's upto you..
I could do it mentally but I can understand the method which would be useful in bigger numbers.
It's faster to do the multipications directly
What the fudge over complication of things ....
For this takes too much times so I calculate normally it's too easy than this இதுக்கு பருத்தி மூட்டு குடோன்லே இருகலாம் 💐👌💖♥
This doesn't seem very hard.
8 x 9 = *72* x 10 = *720* x 11 = 7200 + 720 = *7920*
7920 x 12 is the first point I have to actually think a little bit. Don't even need to write anything down.
The trick is to re-arragen the numbers. Do 9x11 and 8x12, then you have 99x96 which can be written as 100x96 - 96. And all you do then is multiply by 10.
12x9=108
108 x 8 = 864
(800 +64)x11 = 8800+704 = 9504
9504x10=95040
Knowing the neat method for a quick multiplication by 11 means it makes sense to keep that as the second last step, then add a zero for the x 10.
Quicker than the algebraic method.
Omg my kid can do it in her head. I asked her on the way to gymnastics. She said 96x10 is 960 and 960×99 is 96000-960, so 95040
Multiplicar direto é muito mais simples.
Thats very impressive, next challenge is 1 x 1 = ?, No calculator please.
Is it really this difficult to calculate normally ?
8×12 = 96
11×9 = 99
99×96 = 9504 (pretty easy)
And 9504×10 = 95400
Why not just multiply 12x8 11x9 x10= 95,040 less chances of mistake that way. Only in America! LOL
There are a number of permutations of working this out, all much easier and quicker than this 14 step process.
Making simple things difficult😊
95045
Wouldn’t it be easier just to do 720x132 by long multiplication?😉
This is geometric progression, need I say more?
exactly 💯
Congrats on 1M subscribers 🎉🎉🎉
The trick here is to identify that 9x99 is a very easy number to multiply with. 8x12 is even simplier and x10 the simplest of all.
I did it mentally 😂, no need for such complexities
This solution might help for bigger numbers
(10-2)(10-1)(10)(10+1)(10+2)
= (10)(10^2-1^2)(10^2-2^2)
=(10)(100-1)(100-4)
=(10)(9504)
=95040
Bakwas, it can be solved in 10 sec
Use brain calculator it’s much faster
Inefficient... at least there is a moore efficient way. First, group the terms by the easiest way to calculate the last step : 10x(9x11)x(8x12)... because by 11 is easy to find and implies repetition in the part answer --> 10x99x96 --> 10x9504 ---> 95040. That way there is less chance for mistakes and only one real operation to be done by hand the long way (99x96).
Even 99x96 is really easy cause you do 100x96 -96
Before watching:
I just outright multiplied them out, tbh.
12x11 = 132, 12x11x10 = 1320, 12x11x10x9 = (1320)x9 = 11880, 12x11x10x9x8 = (11880)x8 = 95040.
After watching:
The trick shown in the video is very useful for those who aren't very confident in their ability to multiply large numbers together. Definitely worth trying out!
The trick is to re-arragen the numbers. Do 9x11 and 8x12, then you have 99x96 which can be written as 100x96 - 96. And all you do then is multiply by 10.
@bowlchamps37 Kudos! That's the sort of thing I usually look for myself, but in this case I just brute-forced it, lol.
You should know these concepts, otherwise in some hard questions you might get stucked. Brute force is not always a good option.
95040
10×12=120
9×11=99
8×120=2×480=960
960×99=(1000-40)(100-1)
100000-1000-4000+40=100040-5000=95040
Лёгкие пути не для Вас. ☹️
Maybe good practice for algebra but just to get the answer group each pair and add a zero for the times 10 : i.e. 72 x 132 add a zero , 95040
real its a olympiad question?
When the question is of 5 marks ? 😂
It is easy to simple multi plication
How about 96×99×10=(9600-96)×10
Method is useful to know but I feel like just multiplying it would've been much simpler
cannot understand a word she says
Since when is -1^2 = -1?
u made it more tough😜😜
8x9x10x11x12=95,040
This seems stupid
Your method is so complicater
95,045
Promo*SM 👌
Not only did I not need a calculator, I did this in my head in less than 15 seconds. 9x11=99. x10=990. Multiply that by 96. I turned this into (1000-10)(100-4)=100000-5000+40
95040
One step missing!
95040
?
95040
95040
There is an easy way to do it. 9x11= 99= 100-1, 8x12=96 96x(100-1)=9600-96=9504, 9504X10=95040. Everyone can find this answer in a few seconds.
I choose also this way.
I feel like doing 72 x 132 and adding a 0 to the answer would be a much quicker method.
Then you missed the trick. The trick is to re-arragen the numbers. Do 9x11 and 8x12, then you have 99x96 which can be written as 100x96 - 96. And all you do then is multiply by 10.
I did this in my head but I was better at it 15 years ago in high school. It took me a couple minutes.
Woww
ஒஓஓ.. 💖♥💐👌
Well, how many points I score, when I count this "normally", written multiplication.
That's Numberwang!
Learn the math the hard way)))
You didn't follow the order of operations near the end. (Addition an subtraction from left to right)
You do realise it makes no difference
Simply multiply all numbers
tenkyou
Give lecture on stative verbs
Wow PROF thanks👍
95,040
Good
Please explain the logic
haha we indians do this in our mind in high school
The way you communicate mathematics is profoundly childish, inappropriate and needlessly complicated. It lacks more in-depth knowledge.
August through December...duh