When adding or subtracting fractions you must make sure that the denominator is the same.

When adding or subtracting fractions you must make sure that the denominator is the same.

• A. the numerator is the same
• B. the denominator is the same
• C. the fractions are multiplied
• D. the denominators are different

Answer: (B)

To add or subtract fractions you are combining parts of the same-sized unit. The denominator tells you how big each part is, so you need a common denominator to line up the parts before you combine them. If the denominators are already the same, you just add or subtract the numerators and keep that denominator. For example, 2/7 plus 3/7 equals 5/7. If the denominators are different, you convert each fraction to an equivalent fraction with a common denominator, then add or subtract the numerators. For instance, 2/5 and 1/3 become 6/15 and 5/15, which add to 11/15. This is why the statement is correct: you must ensure the fractions share the same denominator to correctly combine the parts.

To add or subtract fractions you are combining parts of the same-sized unit. The denominator tells you how big each part is, so you need a common denominator to line up the parts before you combine them.

If the denominators are already the same, you just add or subtract the numerators and keep that denominator. For example, 2/7 plus 3/7 equals 5/7.

If the denominators are different, you convert each fraction to an equivalent fraction with a common denominator, then add or subtract the numerators. For instance, 2/5 and 1/3 become 6/15 and 5/15, which add to 11/15.

This is why the statement is correct: you must ensure the fractions share the same denominator to correctly combine the parts.