Seashells and Number Machines: Adding and Subtracting Fun!

Math Grades 1st Grade 18:50 Video
Print Lesson Plan Watch Video

Lesson Description

Learn addition and subtraction up to 20 with fun activities! We'll count seashells and use number machines to solve math problems.

Video Resource

Addition and Subtraction up to 20. Simple Math with Kids Academy

Kids Academy

Duration: 18:50
Watch on YouTube

Key Concepts

  • Addition as combining groups
  • Subtraction as taking away from a group
  • Using number machines to solve for unknowns
  • The relationship between addition and subtraction

Learning Objectives

  • Students will be able to add numbers up to 20 by counting and using strategies.
  • Students will be able to subtract numbers within 20 by counting back and understanding the relationship with addition.
  • Students will be able to use the associative property to solve for an unknown number.
  • Students will be able to apply part-part whole strategy.

Educator Instructions

  • Introduction (5 mins)
    Begin by asking students what they know about addition and subtraction. Show the Kids Academy video 'Addition and Subtraction up to 20. Simple Math with Kids Academy'. Tell them to pay attention to how Romo the character adds seashells and how the number machines work.
  • Seashell Addition (10 mins)
    After watching the beginning of the video, pause at [00:08:34]. Ask students to recall how Romo added the seashells. Present addition problems based on the seashell scenario (e.g., 'If Romo finds 7 seashells and then finds 3 more, how many does he have?'). Have students use their fingers or draw pictures to solve the problems.
  • Number Machine Subtraction (15 mins)
    Play the segment of the video demonstrating the number machine. Model a subtraction problem using a number machine drawing on the board. Guide students through solving problems like 8 - 2 = ?. Emphasize that subtraction is taking away.
  • Part-Part Whole (15 mins)
    Explain the part-part-whole concept as shown in the video. Have students work in pairs using manipulatives (counters, blocks) to represent the different parts. Create different scenarios and ask them to find the missing part.
  • Wrap-up (5 mins)
    Review the main concepts of addition and subtraction. Reiterate strategies like counting on and counting back. Ask students what they found most helpful or challenging.

Interactive Exercises

  • Seashell Toss
    Divide the class into teams. Provide each team with a set of numbered index cards (1-10) and a bucket. Call out an addition or subtraction problem (e.g., '5 + 3'). The first team to correctly solve the problem and toss the corresponding index card into the bucket gets a point.
  • Number Machine Challenge
    Create simple number machine worksheets with missing inputs or outputs. Have students work individually to fill in the blanks, applying their understanding of addition and subtraction.

Discussion Questions

  • What happens when we add numbers together?
  • How is subtraction different from addition?
  • Can you think of a time you used addition or subtraction today?
  • Why is it important to know how to add and subtract?

Skills Developed

  • Addition and subtraction fluency
  • Problem-solving skills
  • Critical thinking
  • Using the associative property
  • Applying part-part whole strategy

Multiple Choice Questions

Question 1:

What happens when you ADD?

Correct Answer: Numbers get bigger!

Question 2:

What happens when you SUBTRACT?

Correct Answer: Numbers get smaller!

Question 3:

Romo has 5 seashells. He finds 2 more. How many does he have in all?

Correct Answer: 7

Question 4:

A number machine has the rule '-1'. If you put in 10, what comes out?

Correct Answer: 9

Question 5:

Which number makes this true: 3 + ___ = 5?

Correct Answer: 2

Question 6:

You have 8 cookies and eat 2. How many are left?

Correct Answer: 6

Question 7:

What is 10 + 0?

Correct Answer: 10

Question 8:

Which is the same as 6 - 1?

Correct Answer: 5 - 0

Question 9:

What two numbers can add together to equal 10?

Correct Answer: 5 + 5

Question 10:

What is the missing number 14 - ___ = 4

Correct Answer: 10

Fill in the Blank Questions

Question 1:

Adding means to put numbers ________.

Correct Answer: together

Question 2:

Subtracting means to take numbers ________.

Correct Answer: away

Question 3:

If 4 + 3 = 7, then 7 - 3 = ________.

Correct Answer: 4

Question 4:

The number machine helps us find the ________ number.

Correct Answer: missing

Question 5:

5 + 5 = ________.

Correct Answer: 10

Question 6:

10 - 2 = ________.

Correct Answer: 8

Question 7:

When we add, the answer is ________ than the numbers we start with (usually).

Correct Answer: bigger

Question 8:

When we subtract, the answer is ________ than the number we start with (usually).

Correct Answer: smaller

Question 9:

4 + ___ = 6

Correct Answer: 2

Question 10:

12 - ___ = 7

Correct Answer: 5

Educational Standards

CCSS.Math.Content.1.OA.C.6:Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., 8 + 6 = 8 + 2 + 4 = 10 + 4 = 14); decomposing a number leading to a ten (e.g., 13 - 4 = 13 - 3 - 1 = 10 - 1 = 9); using the relationship between addition and subtraction (e.g., knowing that 8 + 4 = 12, one knows 12 - 8 = 4); and creating equivalent but easier or known sums (e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13). CCSS.Math.Content.1.OA.A.1:Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem. CCSS.Math.Content.1.OA.D.8:Determine the unknown whole number in an addition or subtraction equation relating three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = _ - 3, 6 + 6 = _.

Teaching Materials

Download ready-to-use materials for this lesson:

Student Worksheet Classroom Slides Assessment Quiz Export to Google Docs
Add to Google Classroom

User Actions

Sign in to save this lesson plan to your favorites.

Sign In

Share This Lesson

Related Lesson Plans