Explain why it is necessary to find a common denominator before adding fractions.

A common denominator allows us to add the numerators directly because the fractions represent parts of the same whole.

Which of the following statements is true when renaming fractions to have a common denominator?

Whatever you do to the denominator, you must do to the numerator.

I can add fractions with unlike denominators and simplify the result.

1
When adding fractions with unlike denominators, the first step is to find a common denominator by determining the least common multiple of the denominators.
2
After finding the common denominator, you must rename the fractions so that they have the common denominator, being sure to multiply both the numerator and denominator by the same number to keep the fractions equivalent.
3
Once the fractions have a common denominator, you can add the numerators and keep the denominator the same, then check to see if the resulting fraction can be simplified.