# K.4 Understanding Addition and Subtraction

## Unit Goals

• Students relate counting to addition and solve addition and subtraction story problems within 10.

### Section A Goals

• Understand addition as putting together and subtraction as taking from.

### Section B Goals

• Represent and solve Add To, Result Unknown and Take From, Result Unknown story problems within 10.

### Section C Goals

• Find the value of addition and subtraction expressions within 10.
• Relate addition and subtraction expressions to story problems.

There are

squares.

There are

triangles.

There are

shapes.

There are

shapes.

There are

squares.

There are

triangles.

### Problem 3

Count out 4 counters.

There are

counters.

Count out 6 counters.

There are

counters.

Count out 8 counters.

There are

counters.

### Problem 4

Count out 8 counters.
Take away 2 counters.

There are

counters.

Count out 6 counters.
Take away 2 counters.

There are

counters.

Count out 4 counters.
Take away 2 counters.

There are

counters.

### Problem 5

#### Exploration

Player 1 rolls a cube on the number mat and takes away or adds that number of counters while player 2 is not looking.

Then player 2 figures out what player 1 did.

Players take turns switching roles.

### Problem 6

#### Exploration

Roll a cube onto a number mat.
Count out that number of counters.

Roll a cube again onto the number mat.
Count out that number of counters.
How many counters do you have in all?

### Problem 7

#### Exploration

Pick a number from the list to put in the blank space.

2

7

6

3

Then try the problem you made.

Count out 8 counters.

Take away $$\underline{\hspace{1 cm}}$$ counters.

How many counters are left?

After you try the problem you made, try it again with a different number in the blank space.

Explain.

### Problem 1

Tell your partner a story using the picture.

### Problem 2

Show what happens in the story with counters.

There are 5 snails crawling in the grass.
Then 3 snails came to join them.
Then 2 of the snails crawled away.

### Problem 3

Han gives Jada 2 more connecting cubes.

How many connecting cubes does Jada have now?

### Problem 4

There were 8 cars in the parking lot.

All 8 of the cars left after school.

How many cars are in the parking lot now?

### Problem 5

There were 9 crabs on the beach.

Then 5 of them scurried away into the ocean.

How many crabs are on the beach now?

Circle the representation that matches the story.

### Problem 6

There are 4 cups of milk on the table.

Jada puts 2 more cups of milk on the table.

How many cups are on the table altogether?

Make a drawing to show the story.

### Problem 7

There are 7 crows in the tree.

Then 3 more crows fly into the tree.

How many crows are in the tree altogether?

Show your thinking using drawings, numbers, words, or objects.

### Problem 8

#### Exploration

There are 6 dolphins swimming around the boat.

Complete the story in two different ways.

Solve your problems or share with a partner and solve your partner's problems.

### Problem 9

#### Exploration

Tell a story problem that goes with each drawing.

1.
2.

### Problem 10

#### Exploration

These three story problems are not finished yet.
Finish the story problems with your own questions.
Then solve the story problems you made.

Clare gave him 3 erasers.

Tyler found 2 more pencils.

She lost 1 of her markers.

### Problem 1

There are 5 red apples in the bowl.
Lin puts 3 green apples in the bowl.

How many apples are in the bowl?

Circle the expression that matches the story problem.

$$5 + 3$$

$$5 - 3$$

$$8 - 5$$

### Problem 2

Draw a line from each expression to the matching drawing.

### Problem 3

Find the value of each expression.
Show your thinking using objects, drawings, numbers, or words.

$$3 + 5$$

$$7 - 1$$

### Problem 4

Find the value of each expression.
Show your thinking using objects, drawings, numbers, or words.

$$5 + 0$$

$$5 + 1$$

$$6 + 0$$

$$6 + 1$$

### Problem 5

#### Exploration

Circle the expression that shows 8.

$$1 + 6$$

$$5 + 3$$

$$6 + 3$$

What other expressions can you find that show 8?