Problem Solving (PS) | Re: If {x} is the product of all even integers from 1 to x inclusive, what

{X} is the product of all even integers including x this statement means we have to include in the set even numbers till x. ie if x =5 then even integers from 1 till 5 are 2 and 4 and {5} is the product of 2 and 4.
Now to the question.
{22}+{20}
This can be written as {2*4*6*8*10*12*14*16*18*20*22}+{2*4*6*8*10*12*14*16*18*20} (*=multiplication)
Now in both the curly bracket the common numbers are from 2 to 20. let us take them out.
2*4*6*8*10*12*14*16*18*20(22+1)=2*4*6*8*10*12*14*16*18*20(23)
Numbers
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