Adding Within 20 Word Problems

Master adding within 20 word problems: strategies, visual representations, and practice for 1st grade students.

Adding Within 20 Word Problems
1 Basic Addition
Exercise 1
Sarah has 7 red marbles. Her friend gives her 5 more red marbles. How many red marbles does Sarah have now?
Definition:

Word problem: A mathematical problem presented in a real-life context using words

Solution method:
  1. Identify the numbers in the problem (7 and 5)
  2. Identify what operation is needed (addition)
  3. Set up the equation (7 + 5)
  4. Solve the equation (7 + 5 = 12)
Initial amount
\(7\)
Added amount
\(5\)
Total
\(7 + 5 = 12\)
Step 1: Identify the numbers

Sarah starts with 7 marbles and gets 5 more

Step 2: Determine the operation

She gets MORE marbles, so we add

Step 3: Set up the equation

7 + 5 = ?

Step 4: Solve the equation

7 + 5 = 12

\(7 + 5 = 12\) marbles
Final answer:

Sarah has 12 red marbles now

Applied rules:

• Problem solving: Identify key information in word problems

• Addition: Combine quantities to find totals

• Units: Include the correct units in your answer

2 Making Ten Strategy
Exercise 2
Tom has 9 stickers. His teacher gives him 4 more stickers. How many stickers does Tom have in total?
Definition:

Making ten: Breaking apart one number to make 10 with the other

Break apart 4
\(9 + 1 + 3\)
Make 10
\(10 + 3 = 13\)
Step 1: Identify the numbers

Tom starts with 9 stickers and gets 4 more

Step 2: Use making ten strategy

Break 4 into 1 + 3 to make 10 with 9

Step 3: Add to make 10, then add remainder

(9 + 1) + 3 = 10 + 3 = 13

Step 4: Calculate the final answer

10 + 3 = 13

\(9 + 4 = 13\) stickers
Final answer:

Tom has 13 stickers in total

Applied rules:

• Making ten strategy: Use 10 as a benchmark

• Decomposition: Break apart numbers strategically

• Associative property: Group numbers differently

3 Doubles Plus One
Exercise 3
Emma has 6 toy cars. She gets 7 more toy cars for her birthday. How many toy cars does Emma have now?
Definition:

Doubles plus one: Using a doubles fact and adding one more

Double fact
\(6 + 6 = 12\)
Plus one more
\(12 + 1 = 13\)
Step 1: Identify the doubles fact

6 + 7 is close to 6 + 6

Step 2: Recall the doubles fact

6 + 6 = 12

Step 3: Add the extra one

Since 7 is one more than 6, add 1 to the double

Step 4: Calculate the final answer

12 + 1 = 13

\(6 + 7 = 13\) toy cars
Final answer:

Emma has 13 toy cars now

Applied rules:

• Doubles plus one strategy: Use known doubles facts

• Near doubles: Numbers that differ by 1

• Pattern recognition: See relationships between numbers

More Adding Within 20 Word Problems
4 Counting On Strategy
Exercise 4
There are 8 birds sitting on a fence. 6 more birds join them. How many birds are on the fence now?
Definition:

Counting on: Starting with the larger number and counting up

Start with
\(8\)
Count up 6
\(9, 10, 11, 12, 13, 14\)
Step 1: Identify the numbers

There were 8 birds and 6 more came

Step 2: Use counting on strategy

Start at 8 and count 6 more: 9, 10, 11, 12, 13, 14

Step 3: Identify the final number

The last number counted is the answer

Step 4: Calculate the final answer

8 + 6 = 14

\(8 + 6 = 14\) birds
Final answer:

There are 14 birds on the fence now

Applied rules:

• Counting on strategy: Start with the larger number

• Sequential counting: Count each number in sequence

• One-to-one correspondence: Each count represents one added

5 Commutative Property
Exercise 5
Jake has 4 books on his shelf. His mom brings home 9 more books. How many books does Jake have now?
Definition:

Commutative property: Order of addends doesn't change the sum

Rearrange
\(9 + 4\)
Count on
\(10, 11, 12, 13\)
Step 1: Use commutative property

4 + 9 = 9 + 4 (start with the larger number)

Step 2: Count up from the larger number

Start at 9 and count 4 more: 10, 11, 12, 13

Step 3: Identify the final number

The last number counted is the answer

Step 4: Calculate the final answer

4 + 9 = 13

\(4 + 9 = 13\) books
Final answer:

Jake has 13 books now

Applied rules:

• Commutative property: a + b = b + a

• Efficiency: Start with the larger number

• Counting on: Sequential counting strategy

6 Mixed Numbers
Exercise 6
Lisa collected 5 seashells at the beach. Her brother found 8 more seashells. How many seashells do they have together?
Definition:

Together: A word that indicates addition is needed

Break apart 8
\(5 + 5 + 3\)
Make 10
\(10 + 3 = 13\)
Step 1: Identify the numbers

Lisa has 5 seashells and her brother has 8

Step 2: Use decomposition strategy

Break 8 into 5 + 3 to make 10 with the first 5

Step 3: Add to make 10, then add remainder

(5 + 5) + 3 = 10 + 3 = 13

Step 4: Calculate the final answer

10 + 3 = 13

\(5 + 8 = 13\) seashells
Final answer:

They have 13 seashells together

Applied rules:

• Decomposition strategy: Break numbers into helpful parts

• Make 10 strategy: Use 10 as a benchmark number

• Associative property: Group numbers differently

Visual Infographic: Adding Within 20 Word Problems
📝
➕
🔢
🎯

Word Problems Within 20

Problem-Solving Steps

Sarah has 7 marbles. Gets 5 more.

7 + 5 = 12 marbles

Tom has 9 stickers. Gets 4 more.

9 + 4 = 13 stickers

🔍
Read
📊
Find
➕
Add
✅
Check
Look for Clues
More, added, total, altogether = ADDITION
Within 20
Answer never exceeds 20
Check Work
Does the answer make sense?
💡

Tip: Draw pictures if needed!

Summary: Adding Within 20 Word Problems
Complete Summary and Study Guide

This section provides a comprehensive overview of adding within 20 word problems, including definitions, methods, strategies, and key concepts for 1st grade students.

Definitions

Word Problem: A mathematical problem presented in a real-life context using words.

Addition: Combining quantities to find totals.

Within 20: Problems where the answer is 20 or less.

Context Clues: Words that indicate which operation to use.

Core Rules

• Addition: Look for words like "more," "added," "total," "altogether"

• The sum of two numbers within 20 will never exceed 20

• Order doesn't matter (commutative property)

• Always include the correct units in your answer

Addition Strategies

Counting On: Start with the larger number and count up

Making Ten: Break apart numbers to make 10 first

Doubles Plus One: Use known doubles facts

Number Line: Visual representation of addition

Examples

Counting On: 8 + 5 = start at 8, count 5: 9, 10, 11, 12, 13

Making Ten: 9 + 4 = 9 + 1 + 3 = 10 + 3 = 13

Doubles Plus One: 6 + 7 = 6 + 6 + 1 = 12 + 1 = 13

Commutative: 5 + 8 = 8 + 5 = 13

Tips & Tricks

• Draw pictures to visualize the problem

• Look for clue words that indicate addition

• Start with the larger number to minimize counting

• Always check if your answer makes sense in the context

Common Mistakes

• Missing numbers in the problem

• Forgetting units in the answer

• Not recognizing opportunities to make 10

• Miscounting when using counting on strategy

Questions & Answers

Question: How do I know when to add in word problems? Sometimes I see big numbers and get confused.

Answer: Great question! Here are the clue words to look for that mean you need to add:

Addition words: "more," "added," "total," "altogether," "in all," "combined," "gets," "finds," "collects," "joins," "together"

For example:

  • "Sarah gets 5 more marbles" → ADDITION (she has MORE)
  • "There are 8 birds and 6 more join them" → ADDITION (they COME TOGETHER)

Don't worry about big numbers! Just focus on what's happening in the story. If things are being combined or joined together, it's addition. If you see these clue words, you'll know it's addition!

When in doubt, draw a picture to help visualize what's happening!

Question: My child struggles with word problems. How can I help them break these down into manageable parts?

Answer: Word problems can be challenging! Here are effective strategies:

  • Read slowly: Have your child read the problem multiple times
  • Highlight numbers: Circle or underline the numbers in the problem
  • Draw pictures: Visualize the problem with drawings
  • Act it out: Use manipulatives or act out the scenario
  • Ask questions: "What do I know?" "What do I need to find?"

For example, in "Lisa has 5 seashells and her brother finds 8 more":

  1. First: What do I know? Lisa has 5, brother finds 8
  2. Second: What do I need to find? Total seashells
  3. Third: What operation? "More" means add
  4. Fourth: Solve: 5 + 8 = 13

Practice with simple word problems first, then gradually increase complexity. Consistent practice will build confidence!

Question: Do I always have to write the number sentence? Can't I just count in my head?

Answer: That's a great question! Writing the number sentence is really helpful, even if you can count in your head. Here's why:

  • It helps you organize your thinking
  • You can check your work more easily
  • It prepares you for harder problems later
  • Teachers can see how you solved the problem

For example, if the problem is "Tom has 9 stickers and gets 4 more," writing "9 + 4 = 13" helps you remember what you did.

As you get older and the problems get harder, writing number sentences becomes even more important!

It's like showing your work - it helps everyone understand how you got your answer.

Even if you solve it in your head, writing the number sentence is good practice!