Question 48751
2/5=x-2/20 or 2/5=x-1/10 or 2/5+1/10=x or 4/10+1/10=x or 5/10=x or x=1/2

proof 2/5=1/2-2/20 or 2/5-1/2+2/20=0 or 2/5-1/2+1/10=0 or 4/10-5/10+1/10=0 or 

(4-5)/10+1/10=0 or -1/10+1/10=0 or 0=0