Writing Number Sentences to Solve Problems!

Math Grades 1st Grade 3:57 Video
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Lesson Description

Learn how to write number sentences (equations) to solve simple addition word problems. We'll use the equal sign and addition symbol to show our thinking!

Video Resource

How to Write a Number Sentence or Equation

Miacademy Learning Channel

Duration: 3:57
Watch on YouTube

Key Concepts

  • Number sentences (equations)
  • Addition
  • Equal sign (=)

Learning Objectives

  • Students will be able to define a number sentence (equation).
  • Students will be able to write a number sentence to represent a simple addition word problem.
  • Students will be able to solve simple addition word problems using number sentences.

Educator Instructions

  • Introduction (5 mins)
    Begin by asking students what they already know about number sentences. Show examples like 2 + 3 = 5 and 7 - 2 = 5. Explain that today, they will learn how to write their own number sentences to solve word problems.
  • Video Viewing (5 mins)
    Play the "How to Write a Number Sentence or Equation" video from Miacademy Learning Channel. Encourage students to pay attention to how Kiley uses number sentences to solve the marble problem.
  • Discussion (5 mins)
    After the video, discuss the key points. What is a number sentence? What symbols do we use in a number sentence? Why is the equal sign important?
  • Guided Practice (10 mins)
    Present a simple addition word problem on the board: "Sarah has 3 apples. Tom has 2 apples. How many apples do they have together?" Guide students through writing the number sentence: 3 + 2 = ?. Then, have them solve the problem and write the answer: 3 + 2 = 5.
  • Independent Practice (10 mins)
    Provide students with 2-3 more word problems to solve independently. Examples: * "There are 5 red balloons and 1 blue balloon. How many balloons are there in all?" * "A cat has 4 kittens. Another cat has 3 kittens. How many kittens are there altogether?"
  • Wrap-up (5 mins)
    Review the answers to the independent practice problems. Ask students to share how writing the number sentence helped them solve the problem. Reinforce that a number sentence is a tool to help them show and solve math problems.

Interactive Exercises

  • Word Problem Match
    Write several word problems on one set of cards, and corresponding number sentences on another set of cards. Have students match the word problem to the correct number sentence.

Discussion Questions

  • What is a number sentence?
  • What does the equal sign (=) mean?
  • Why is it helpful to write a number sentence to solve a word problem?

Skills Developed

  • Problem-solving
  • Critical thinking
  • Number sense

Multiple Choice Questions

Question 1:

Which of these is a number sentence?

Correct Answer: 2 + 1 = 3

Question 2:

What does the + sign mean?

Correct Answer: Add

Question 3:

What does the = sign mean?

Correct Answer: The same as

Question 4:

Lily has 2 cookies. Her friend gives her 3 more. How many cookies does Lily have?

Correct Answer: 5

Question 5:

Which number sentence shows Lily's cookies?

Correct Answer: 2 + 3 = 5

Question 6:

Tom has 4 toy cars. Ben has 1 toy car. How many toy cars do they have in all?

Correct Answer: 5

Question 7:

Which number sentence shows the toy cars?

Correct Answer: 4 + 1 = 5

Question 8:

Which symbol do we use to show something is the same?

Correct Answer: =

Question 9:

If we want to find out how many in all, do we add or take away?

Correct Answer: Add

Question 10:

What is the answer to 1 + 2 = ?

Correct Answer: 3

Fill in the Blank Questions

Question 1:

A number sentence uses numbers and ___________.

Correct Answer: symbols

Question 2:

The plus sign (+) means to ___________.

Correct Answer: add

Question 3:

The equal sign (=) means ___________.

Correct Answer: same

Question 4:

3 + 1 = ____

Correct Answer: 4

Question 5:

If you have 2 toy cars and get 2 more, you now have ____ toy cars.

Correct Answer: 4

Question 6:

We can write 2 + 2 = ____ to show how many toy cars you have.

Correct Answer: 4

Question 7:

A number sentence is also called an ___________.

Correct Answer: equation

Question 8:

5 + 0 = ____

Correct Answer: 5

Question 9:

In the number sentence 4 + 2 = 6, the answer is ____.

Correct Answer: 6

Question 10:

If the word problem asks "How many in all?" we usually __________.

Correct Answer: add

Educational Standards

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.7:Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false? 6 = 6, 7 = 8 - 1, 5 + 2 = 2 + 5, 4 + 1 = 5 + 2. 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).

Teaching Materials

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