Addition and Subtraction Word Problems Within 20

Word problems are like short math stories. To solve them, we need to read the story, find the numbers, and decide if we need to add ($+$) or subtract ($-$). Let's look at how to solve different types of word problems using numbers up to 20!

Addition Word Problems: "How Many in All?"

Addition problems usually ask us to put things together. Look for clue words like in all, altogether, total, or more.

Example: There are $8$ red balls and $6$ blue balls. How many balls are there in all?

• Clue: "in all" means we need to add.
• Equation: $8 + 6 = 14$
• Answer: There are $14$ balls in all.

Another type of addition problem gives someone more of something:

Example: Sam has $5$ more books than Tom. Tom has $8$ books. How many does Sam have?

• Clue: Sam has "more" than Tom's $8$ books.
• Equation: $8 + 5 = 13$
• Answer: Sam has $13$ books.

Subtraction Word Problems: "How Many Are Left?"

Subtraction problems often happen when things are taken away. Look for clue words like left, gave away, lost, or ate.

Example: Lily had $15$ crayons. She gave $4$ crayons to her friend. How many crayons does Lily have left?

• Clue: "gave" and "left" mean we need to subtract.
• Equation: $15 - 4 = 11$
• Answer: Lily has $11$ crayons left.

Comparison Word Problems: "How Many More?"

Sometimes, a story asks us to compare two amounts to see who has more or who has fewer. Even though it says "more," we usually use subtraction to find the difference between the two numbers.

Example: Amy has $12$ stickers. Ben has $7$ stickers. How many more stickers does Amy have?

• Clue: "How many more" means we need to find the difference.
• Equation: $12 - 7 = 5$
• Answer: Amy has $5$ more stickers than Ben.

Quick Tips for Word Problems

1. Read carefully: What is the story telling you?
2. Find the numbers: Circle the numbers in the story.
3. Look for clues: Decide if you need to add ($+$) or subtract ($-$).
4. Write the equation: Write down your math sentence and solve it!