Section 1
Add Fractions with a Common Denominator
Property
If , , and are numbers where , then
To add fractions with a common denominator, add the numerators and place the sum over the common denominator.
In this Grade 4 lesson from The Art of Problem Solving: Prealgebra (AMC 8), students learn how to add and subtract fractions by applying the distributive property of division over addition and subtraction to combine fractions with like denominators. The lesson emphasizes a common misconception — that adding numerators and denominators separately is incorrect — and builds toward finding common denominators for fractions with unlike denominators. Students practice simplifying results and interpreting fraction addition and subtraction on the number line.
Section 1
Add Fractions with a Common Denominator
If , , and are numbers where , then
To add fractions with a common denominator, add the numerators and place the sum over the common denominator.
Section 2
Subtract Fractions with a Common Denominator
If , , and are numbers where , then
To subtract fractions with a common denominator, we subtract the numerators and place the difference over the common denominator.
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Section 1
Add Fractions with a Common Denominator
If , , and are numbers where , then
To add fractions with a common denominator, add the numerators and place the sum over the common denominator.
Section 2
Subtract Fractions with a Common Denominator
If , , and are numbers where , then
To subtract fractions with a common denominator, we subtract the numerators and place the difference over the common denominator.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter