Answer: The only possible number is +1
Step-by-step explanation:
Let the number be x then according to the question
[tex]20\times x^{2}=20\times x[/tex]
=>[tex]20x(x-1)=0[/tex]
=>[tex]x=0,1[/tex]
But x=0 is not possible therefore
=>[tex]x=+1[/tex]
Thus the only possible number is +1