Subtraction and Number Line Concepts

The video tutorial covers subtraction using open number lines, focusing on counting back in groups of ten. It provides examples of subtracting numbers like 30 minus 20 and 95 minus 30, demonstrating the use of hops on a number line. The tutorial also includes practical applications, such as subtracting beads and balloons, and encourages higher-order thinking by solving subtraction problems with number lines. Finally, it prepares students for assessments by reviewing test-like questions and solutions.

What is the main concept introduced in this section?

• Counting forward to add

• Counting back to subtract

• Multiplying using number lines

• Dividing using number lines

If you start at 30 and make two hops of 10 backwards, where do you end up?

• 20

• 10

• 0

• 5

Starting at 95, how many hops of 10 do you need to reach 65?

• 2

• 3

• 5

• 4

What is the result of 21 minus 20 using a number line?

• 11

• 0

• 10

• 1

How can you subtract 10 from 15 using a number line?

• Move backward 10

• Move forward 10

• Move backward 5

• Move forward 5

Lisa has 25 beads and gives 10 away. How many does she have left?

• 15

• 10

• 5

• 20

If a person has 43 balloons and gives away 20, how many are left?

• 13

• 33

• 3

• 23

What equation can be solved using a number line starting at 80 and subtracting 20?

• 80 - 10 = 70

• 80 - 30 = 50

• 80 - 40 = 40

• 80 - 20 = 60

Which of the following is a correct subtraction scenario from a number line?

• 90 - 30 = 70

• 90 - 40 = 50

• 90 - 10 = 60

• 90 - 20 = 80

How many hops of 10 are needed to count back from 90 to 50?

• 5

• 4

• 3

• 6