Your equation would be correct if you would place parentheses correctly. This is your reasoning, usingNot this: 100/x - 2.5 = 100/x+2 But this: 100/x - 2.5 = 100/(x+2) When typing algebra all on 1 line, if a numerator or a denominator contains more than just 1 number, or just 1 letter, you must type a left parenthesis "(" to indicate where the numerator or denominator starts, and a right parenthesis ")" to indicate where it ends. Edwin