Number 19 you are comparing one measurement to another. Since it says 1/2 inch equals 4 ft, we want to find out how many more inches are needed if the given scale was 2/3 = 4 ft. Now lets find a common denominator for both scales stated in inches. We have 2/3 inch and 1/2 inch. Our denominator are the bottom parts of the fraction where we need to find a common factor for the denominator so we can add or subtract fractions. We have a 3 and a 2. You may always use the multiplication between two denominators to find a common factor such as 3 times 2 which equals 6 for both denominators. Now we multiplied the 3 by 2 to get 6 so the top part (numerator needs to be multiplied the the 2 because we changed the bottom part by 2 as well. You should notice that when you reduce your fraction now 4/6 is 2/3. Just a self check example there. As for 1/2 we multiplied a 3 to get 6 for the denominator so we need to multiply the numerator by 3 as well. You now should have 4/6 and 3/6. Since the question asks for how many more inches we need to subtract 4/6 from 3/6 and we get 1/6 inch for our answer.
