Adding Up and Taking Away: Understanding How Addition and Subtraction are Related!

Math Grades 1st Grade 2:05 Video
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Lesson Description

Learn how addition and subtraction are connected! We'll use fun objects to see how adding two numbers is related to taking them away.

Video Resource

Relating addition and subtraction | Basic addition and subtraction | Early Math | Khan Academy

Khan Academy

Duration: 2:05
Watch on YouTube

Key Concepts

  • Addition
  • Subtraction
  • Inverse Relationship

Learning Objectives

  • Students will be able to identify the relationship between addition and subtraction.
  • Students will be able to use addition facts to solve related subtraction problems.

Educator Instructions

  • Introduction (5 mins)
    Begin by asking students what they already know about adding and subtracting. Show the Khan Academy video 'Relating addition and subtraction | Basic addition and subtraction | Early Math | Khan Academy'. Tell them to pay attention to how adding and taking away are connected.
  • Guided Practice (10 mins)
    After watching the video, revisit the examples used (2 + 3 = 5, 5 - 2 = 3, 5 - 3 = 2). Use physical objects like blocks or counters to demonstrate these equations. Ask students to explain what's happening in each step.
  • Independent Practice (10 mins)
    Give each student a worksheet with simple addition problems (sums up to 10). For each addition problem, ask them to write two related subtraction problems. For example, if the problem is 4 + 1 = 5, they should write 5 - 4 = 1 and 5 - 1 = 4.
  • Wrap Up (5 mins)
    Review the main concepts of the lesson. Ask students to share what they learned about how addition and subtraction are related. Reiterate that knowing addition facts helps with subtraction.

Interactive Exercises

  • Number Bond Activity
    Draw number bonds on the board. Fill in two of the circles with numbers and have students figure out the missing number using either addition or subtraction. For example, a number bond with 3 and 2 filled in would require students to find the total (5).
  • Story Problem Creation
    Give students a number sentence (e.g., 6 + 2 = 8). Have them create a short story problem that represents the addition sentence. Then, have them create a related subtraction story problem (e.g., 8 - 2 = 6).

Discussion Questions

  • What happens when you add two numbers together?
  • What happens when you take away one of those numbers from the total?

Skills Developed

  • Addition and Subtraction Fluency
  • Problem-Solving
  • Understanding Mathematical Relationships

Multiple Choice Questions

Question 1:

If 2 + 4 = 6, which of these is also true?

Correct Answer: 6 - 4 = 2

Question 2:

Which number sentence is related to 3 + 1 = 4?

Correct Answer: 4 - 3 = 1

Question 3:

If you have 5 cookies and eat 2, how many are left? This is like saying:

Correct Answer: 5 - 2 = ?

Question 4:

What is the missing number? 1 + ? = 3

Correct Answer: 2

Question 5:

What is the missing number? 4 - ? = 2

Correct Answer: 3

Question 6:

If 3 + 3 = 6, then 6 - 3 = ?

Correct Answer: 3

Question 7:

Which of these shows that addition and subtraction are related?

Correct Answer: 2 + 2 = 4 and 4 - 2 = 2

Question 8:

If I know 5 + 0 = 5, what subtraction problem do I also know?

Correct Answer: 5 - 5 = 0

Question 9:

Which sign means to take away?

Correct Answer: -

Question 10:

Which sign means to put together?

Correct Answer: +

Fill in the Blank Questions

Question 1:

Adding is putting numbers ___________.

Correct Answer: together

Question 2:

Subtracting is taking numbers ___________.

Correct Answer: away

Question 3:

2 + 1 = 3. So, 3 - 1 = _______.

Correct Answer: 2

Question 4:

4 + 2 = 6. So, 6 - 2 = _______.

Correct Answer: 4

Question 5:

If I have 3 apples and get 2 more, I have 5 apples. 5 - 2 = _______.

Correct Answer: 3

Question 6:

5 + 1 = ______

Correct Answer: 6

Question 7:

Knowing 1 + 1 = 2 helps you know 2 - 1 = _______.

Correct Answer: 1

Question 8:

The opposite of adding is ___________.

Correct Answer: subtracting

Question 9:

When you subtract, the number gets ___________.

Correct Answer: smaller

Question 10:

When you add, the number gets ___________.

Correct Answer: bigger

Educational Standards

CCSS.Math.Content.1.OA.B.4:Understand subtraction as an unknown-addend problem. For example, subtract 10 - 8 by finding the number that makes 10 when added to 8. CCSS.Math.Content.1.OA.C.6:Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as... using the relationship between addition and subtraction. CCSS.Math.Content.1.OA.D.7:Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false.

Teaching Materials

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