Exploring Fractions and Addition Properties

Miss Nelson teaches lesson 7.9 on fractions and properties of addition. She explains the commutative and associative properties, using examples to show how they help in mental math. The lesson includes a problem involving distances between lighthouses, demonstrating how to apply these properties to add fractions efficiently. The video concludes with a recap of the key points and encourages students to practice on page 301 of their math book.

What is the main topic of Lesson 7.9?

• Geometry and Measurement

• Multiplication and Division

• Decimals and Subtraction

• Fractions and Properties of Addition

What does the commutative property of addition state?

• The sum changes when the order of addends is changed.

• The sum remains the same when the order of addends is changed.

• The sum changes when the grouping of addends is changed.

• The sum remains the same when the grouping of addends is changed.

Which of the following is an example of the commutative property?

• 4 + 5 = 5 + 4

• 4 + (5 + 6) = (4 + 5) + 6

• 4 - 5 = 5 - 4

• 4 * 5 = 5 * 4

What does the associative property of addition state?

• The sum changes when the order of addends is changed.

• The sum changes when the grouping of addends is changed.

• The sum remains the same when the order of addends is changed.

• The sum remains the same when the grouping of addends is changed.

Which of the following is an example of the associative property?

• 4 - 5 = 5 - 4

• 4 * 5 = 5 * 4

• 4 + 5 = 5 + 4

• 4 + (5 + 6) = (4 + 5) + 6

What is the first step in solving the lighthouse distance problem?

• Subtract the distances from each other.

• Use the associative property to group all addends.

• Add all the distances together at once.

• Use the commutative property to group fractions with a sum of 1.

Which fractions are grouped together first in the lighthouse problem?

• 5/10 and 6/10

• 6/10 and 5/10

• 5/10 and 5/10

• 6/10 and 6/10

What is the final distance calculated in the lighthouse problem?

• 148.6 miles

• 148.0 miles

• 105.6 miles

• 143.6 miles

Why is it useful to group fractions that sum to a whole number first?

• It ensures the sum is always correct.

• It helps avoid changing between mixed numbers and fractions.

• It makes the calculation more complex.

• It simplifies the subtraction process.

What should you do if you have questions about the lesson?

• Leave a message for the teacher.

• Skip the lesson.

• Try to solve it on your own.

• Ask a friend.