2 1 × 3 2 × 4 3 × 5 4 × … × 1 0 9 = ?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
This seems more complicated than necessary. Just cancel before multiplying. Everything cancels except the 1 and the 10.
Log in to reply
It's actually simpler than writing out all of the fractions and cancelling. The 9! is the representation of that and shows that 9! cancels out 9!. Probably the simplest possible way to write it.
Could you articulate your equalities a bit more--still not following.
Still not clear on what 9!/10! means and where it came from, and then where the next fraction equality came from (9!/9!(10))
Log in to reply
Robert, 9! means "nine factorial." It is a simple way to write sum of 9x8x7x6x5x4x3x2x1, which is what you do when you multiply all the numerators of this equation. The denominator is 10!. This is what you're doing when you multiply across all of the denominators. So the simplest way to way to write the equation is 9!/10! . Then, to go further, you factor out 9! from the fraction by dividing 9! from both the numerator and the denominator. So 9! divided by 9! = 1. And 10! divided by 9! = 10. That's how you get 1/10 or 0.1
It has yet another simple explanation.
I typed correct answer(0. 1)But it showing that these values are not allowed
I'm mad. I kept trying to answer 1/10 & it wouldn't accept my answer, only to find out after checking the solution afterwards I needed to put the dumb answer as a decimal!
But why, when the problem statement used fractions, is not the answer 1/10 deemed acceptable?
@Jackson Abascal : You should cancel BEFORE multiplying.
Before you explained, I was totally confused! but now, ALL BETTER!
Clarification to above reply: I understand the meaning of 9! / 10!
Not understanding how 9! / 9! (10) comes into being.
Log in to reply
10! is simply 10 x 9 x8 x7 x6 x5 x4x3x2x1. which is the same as 9!(10)
The denominator of the previous fraction is cancelled by the numerator of the next fraction.This process gives 1 0 1 = 0 . 1
just as i did!
Ohhhhhhhh this makes much more sense now
Oh, I cannot believe I did not see that before! It's so simple now!!!
simple, removing the numeraror/denominator remaining will be 1/10
2 1 | * | 3 2 | = | 3 1 |
3 1 | * | 4 3 | = | 4 1 |
4 1 | * | 5 4 | = | 5 1 |
5 1 | * | 6 5 | = | 6 1 |
6 1 | * | 7 6 | = | 7 1 |
7 1 | * | 8 7 | = | 8 1 |
8 1 | * | 9 8 | = | 9 1 |
9 1 | * | 1 0 9 | = | 1 0 1 |
1 0 1 | = | 0.1 |
Ok, now it makes sense even for me, :) thanx!
Just use cancellation. For example:
1/2 x 2/3 = 1/3, because the 2s cancel out.
1/3 x 3/4 = 1/4, because the 3s cancel out.
1/4 x 4/5 = 1/5, because the 4s cancel out.
Just continue this to the end, and you are left with 1/10.
1/10 = 0.1, so the answer is 0.1
Отлично! Самое простое объяснение, без всяких фракталов.
1/10... the 2s cancels each others, the 3s, the 4s...
2 1 x 3 2 x 4 3 x 5 4 x 6 5 x 7 6 x 8 7 x 9 8 x 1 0 9 multiply it all together = 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 1 0 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 rearrange the terms and split back into new fractions = 2 2 x 3 3 x 4 4 x 5 5 x 6 6 x 7 7 x 8 8 x 9 9 x 1 0 1 turn fractions that are 1 into 1 = 1 x 1 x 1 x 1 x 1 x 1 x 1 x1 x 1 0 1 1 goes away in multiplication = 1 0 1
Cross out repeating numbers.
Cut out the denominator of the fraction by the next one - which means: - the answer is 0.1
All denominators are cancelled by the next of numerator. Only 1/10 will left so the answer is 0.1
Take logarithm both sides , assume right side as x , each successive log is canceled by previous member , in the end we are left with logx=log(1/10) , on comparing we get x=0.1
( n + 1 ) ! n ! , if n eq 9 we got 1 0 ! 9 ! , eq 9 ! ( 1 0 ) 9 ! simplified by 1 0 1 .
9!/10! =9!/9!*10 =1/10 =0.1
The dr. Of the previous fraction is cancelled by the nr of next fraction. Then it gives 1/10=0.1
the product of the numerators will be x, the product of the denominators will be 10x, therefpre the answer willbe x/10x=1/10
All of the numerators and denominators cancel except 1 and 10, ergo 1/10 or .1
This fraction is equivalent to 9!/10! since 10!=9!*10, the 9! is cancelled out with only a ten left, so we have 1/10, which is 0.1.
All the numbers cancel off except 1 & 10 Leaving 1/10 = 0.1
Remove 2, 3, 4, 5, 6, 7, 8, and 9. And you will find 1/10 and it means 0.1
9! / 10, then we can cancel 9! making it 1/10 =0.1
The way I did it (which was a bit too much) was: Let n = 1 , therefore, the product is written as: n + 1 n × n + 2 n + 1 × n + 3 n + 2 × n + 4 n + 3 × n + 5 n + 4 × n + 6 n + 5 × n + 7 n + 6 × n + 8 n + 7 × n + 9 n + 8 But most of the the denominators cancel each other, leaving: n × n + 9 1 = 1 0 1 = 0 . 1 ■
cancellation Method only,so we get 0.1 .. :)
Problem Loading...
Note Loading...
Set Loading...
Since the multiplication of a series of fractions is the product of all the numerators over the product of all the denominators, we can find the answer with 1 0 ! 9 ! = 9 ! ( 1 0 ) 9 ! = 1 0 1 = 0 . 1 .