Double Digit Addition with Open Number Line

The video tutorial demonstrates how to solve double-digit addition problems using an open number line. It begins by explaining the concept of an open number line and how it can be used to solve addition problems. The instructor then decomposes the number 42 into tens and ones to illustrate the process of using the number line for addition. Two methods are shown to solve the problem 27 + 42, both resulting in the sum of 69. The tutorial emphasizes the flexibility of using number lines and encourages students to explore different ways to decompose numbers.

What is an open number line?

• A number line with pre-assigned numbers

• A blank number line with no pre-assigned numbers or tick marks

• A number line with only even numbers

• A number line with only odd numbers

What does decomposing a number mean?

• Breaking a number into its place value pieces

• Multiplying numbers

• Subtracting numbers

• Combining numbers together

How is the number 42 decomposed in the video?

• Into 40 and 2

• Into 30 and 12

• Into 20 and 22

• Into 50 and -8

How many hops of 10 are made to solve 27 + 42?

• 2

• 3

• 5

• 4

What is the final value obtained when solving 27 + 42 using the first method?

• 59

• 67

• 69

• 68

In the alternative method, what is done first?

• Hopping the tens

• Hopping the ones

• Subtracting the smaller number from the larger number

• Adding both numbers directly

How many little hops are made in the alternative method?

• 2

• 4

• 3

• 1

What is the value after making two little hops in the alternative method?

• 31

• 30

• 29

• 28

What is the final value obtained when solving 27 + 42 using the alternative method?

• 67

• 69

• 59

• 68

What is the purpose of using different methods to solve the same problem?

• To confuse students

• To waste time

• To make the problem more difficult

• To verify the solution and understand different approaches