Question

proof 2+2=5 in a very simple way

Answer 1

20-20 = 25-25. (since, 0=0)
5×4 - 5×4 = 5×5 - 5×5
4(5 - 5) = 5(5 - 5)

4 = 5(5 - 5)/(5 - 5). [(5-5)and(5-5) become cancel out]

4 = 5

Then,
2 + 2 =5
Hence proved

Answer 2

Answer:

The answer is that the equation 2+2=5 is wrong.

Step-by-step explanation:

Why do some claim that 2+2=5? The solution given by them are as follows:

Method:

20-20=25-25 [as both are 0]

4×5-4×5=5×5-5×5

4(5-5)=5(5-5) [after factorizing]

We know that, 2+2=4

4=5 [(5-5) will cancel out as they both are common on both the sides]

∴2+2=5

So, what is wrong in this method. Let us find out:

(5-5) was cancelled from both the sides as it was common. Mathematically, cancelling out does not make any sense. But we use cancellation to save our time. Hence this must be having certain limitations and cannot be used in all conditions. So, why can't we use cancellation here. To understand this lets us understand when cancellation is used. Look at the equation:

a+b=b+c

By transposing b on the right hand side we can rewrite it as:

a=b+c-b

After rearranging:

a=b-b+c

a=c

We can very well understand that the change in sign will give us b-b which will finally remove b from the equation as we can ignore zero. In this case we can use cancellation. Let us look at another equation:

x×y=z×y

By transposing y on the right hand side, we can rewrite the equation as:

x=z×y÷y

We know that if a non-zero number is divided by the same number, you get 1, and 1 multiplied by any number will give you the number itself. So, here also cancellation is possible.

Returning to our main equation, in the line 3 of the Method:

4(5-5)=5(5-5)

Here cancelling (5-5) is not possible as (5-5) is not a non-zero number. Cancelling (5-5) would lead to an error. What kind of error? Here is the error:

4(5-5)=5(5-5)

4=5×(5-5)/(5-5)

0/0 is not possible and is an error. Hence the Method is wrong.