Adding and Subtracting Fractions — Putting Parts Together

Memory Verse "Two are better than one, because they have a good return for their labor." — Ecclesiastes 4:9 (NIV)

Learning Objective

Students will learn how to add and subtract fractions with like and unlike denominators.

Lesson Content

Adding fractions with the same denominator is simple: just add the numerators and keep the denominator the same. For example, 2/5 + 1/5 = 3/5. You are combining parts that are the same size.

Subtracting fractions with the same denominator works the same way: subtract the numerators. For example, 7/8 - 3/8 = 4/8, which simplifies to 1/2.

When fractions have different denominators, you must first find a common denominator. For example, to add 1/3 + 1/4, change them to 4/12 + 3/12 = 7/12. To subtract 1/2 - 1/3, change them to 3/6 - 2/6 = 1/6.

Adding and subtracting fractions is useful in everyday life — combining ingredients in a recipe, figuring out how much of a project is done, or adding up time spent on chores. Just as Ecclesiastes 4:9 says 'two are better than one,' putting fractions together helps us see the bigger picture of God's orderly creation.

Hands-On Activity

Solve these problems: 1/4 + 2/4, 3/8 + 2/8, 5/6 - 1/6, 1/2 + 1/3, 3/4 - 1/3, and 2/5 + 1/10. Show your work by finding common denominators. Then create your own word problem involving adding fractions.

Discussion Questions

  • Why do fractions need the same denominator before you can add or subtract them?
  • When might you need to add fractions in real life?
  • How does working with fractions teach us about order and precision?
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