At her birthday party, Ms. Willow would not give her age directly. She said, 'If you add the year of my birth to this year, subtract the year of my 80th birthday and the year of my 30th birthday, and then add my present age, the result is 42.'

example 2 – simplify: step 1: completely factor both the numerators and denominators of all fractions. step 2: change the division sign to a multiplication sign and flip (or reciprocate) the fraction after the division sign; essential you need to multiply by the reciprocal. step 3 : cancel or reduce the fractions.