In this situation, you are dividing 42 by 2 1/3. What you would need to do is make 2 1/3 an improper fraction. You'd multiply the denominator by the whole number and then add the numerator. Once
you get that (It's 7), you would use the same denominator as the original fraction. Now you would use what I call, the keep, change and flip method. That is basically making 42 a fraction (42/1), changing the division sign into a multiplication sign, and flipping the numerator and denominator so that it will be 3/7. You then evaluate the equation, and your answer should be 126/7. To get the amount of days the bag of dog food will last, you need to divide 126÷7. You will see 18 and a bunch of numbers after a decimal, but just use 18 as your answer. Hope this will help you!