This video tutorial teaches how to add and subtract numbers within 20 using an open number line. It begins with a review of basic addition and subtraction concepts, including the commutative property of addition. The tutorial demonstrates how to use an open number line for both addition and subtraction, providing examples and addressing common misunderstandings, such as the non-commutative nature of subtraction. The lesson concludes with a summary of the key points covered.

What is the primary method used to add numbers on an open number line?

• Dividing

• Counting on

• Counting down

• Multiplying

What does it mean to subtract a number?

• To combine quantities

• To divide quantities

• To take away or remove

• To multiply quantities

Which property states that numbers can be added in any order?

• Distributive Property

• Associative Property

• Identity Property

• Commutative Property

Which of the following is true about the commutative property?

• It applies to multiplication and division

• It only applies to addition

• It applies to both addition and subtraction

• It only applies to subtraction

What is the sum of 5 and 3 using the commutative property?

• 10

• 9

• 8

• 7

If you start at 12 on an open number line and add 6, where do you land?

• 16

• 22

• 20

• 18

When adding 7 and 9 on an open number line, why is it easier to start with 9?

• 9 is a larger number

• 9 is a smaller number

• 9 is a prime number

• 9 is an even number

What is the result of counting back 6 spaces from 18 on an open number line?

• 10

• 12

• 14

• 16

What is a common misunderstanding about subtraction?

• Subtraction is distributive

• Subtraction is reflexive

• Subtraction is associative

• Subtraction is commutative

What is the result of subtracting 6 from 14 on an open number line?

• 12

• 6

• 8

• 10