Explain why you cannot add or subtract fractions with unlike denominators while you can add or subtract fractions with like denominators. Include one or more real-world examples in your explanation.
You cannot add or subtract fractions with unlike denominators because the denominators represent different units of measurement. For example, if you have two fractions with denominators of 4 and 6, the 4 represents four pieces and the 6 represents six pieces. If you add or subtract these fractions, you would be combining pieces of different sizes, which would not make sense.
A real-world example of this would be if you were trying to add or subtract two different types of currency. For example, if you had one dollar and one euro, you could not add or subtract them because they are different units of measurement.