John says that when you add 7 2/5 to 2 1/5, you must add the whole numbers together first (7 + 2 = 9).
Then you add the numerators together (2 + 1 = 3) and you add the denominators together (5 + 5 = 10).
So the answer is 9 3/10.
Unfortunately, John's strategy is incorrect. Solve this problem and then briefly explain the flaw in John's reasoning.
To add the fractions 7 2/5 and 2 1/5, you should first add the whole numbers together (7 + 2 = 9).
Then, you can add the fractions by finding a common denominator. In this case, both fractions already have the same denominator of 5, so you can simply add the numerators together (2 + 1 = 3).
So, the correct answer is 9 3/5, not 9 3/10 as John suggested.
The flaw in John's reasoning is that he incorrectly added the denominators together. Adding the denominators is not necessary in this case since the fractions already have the same denominator. Adding the denominators together would only be required if the fractions had different denominators.