Mental Math Addition and Subtraction

I Can Use Mental Math Strategies For Subtraction.

Apply It

Example: Read IT

Kendra has some strawberries. She eats 5 of them. Now she has 8 strawberries. How many strawberries did Kendra start with?

Write an equation with an unknown number. You can show the numbers in a number bond.

? - 5 = 8

Kendra eats 5 strawberries. Then she has 8 strawberries. Add 8+5 to find the unknown number that she started with.

8+5=13. So, 13-5=8

Apply It- Worksheet page 45 or notebook

Greg has 18 dollars. He spends 9 dollars on a game. How much money does Greg have left?

(show you work)

Multiple Choice

Greg has dollars. He Sends 9 dollars on a game. How much money does Greg have left?

• 18-9=9

• 18-8=10

• 7-7=0

• 9-4=5

Find 12-8 by counting on.

show your work on your worksheet or notebook.

Multiple Choice

Find 12-8= by counting on.

• 4

• 7

• 5

• 3

Now let us review our answer.

What number did you start with?

What do you know about all fact Families?

Stop and think!!! Then share!!!

Multiple Select

Which equations would be in the fact family for the number bond?

• 12=7+5

• 19=12+7

• 7=12-5

• 12=5+7

• 5= 12-7

Open Ended

Lily chose 19=12+7 as the correct answer. How did she get that answer?

Lily chose 19=12+7 as the correct answer. How did she get that answer?

Now let's discuss what you think on how Lily got her answer.

Multiple Choice

Exit Ticket:

What is 15-8=

• 9

• 8

• 7

• 6

I Can Practice Using Mental Math Strategies For Subtraction

Following along worksheet page 47 and 48

Eli buys 12 oranges. He uses 7 of them to make a fruit salad. How many oranges does he have left?

Think about how making ten can help you solve this problem. Write it in your notebook or on your worksheet.

Open Ended

Eli buys 12 oranges. He uses 7 of them to make a fruit salad. How many oranges does he have left?

Please put your answer in a sentence.

Eli has ______ oranges left.

Leti has some stickers. She gives 10 stickers to her bother. Leti has 10 stickers left. How many stickers did Leti have to begin with?

Make you number sentence.

Multiple Choice

Leti has some stickers. She gives 10 stickers to her bother. Leti has 10 stickers left. How many stickers did Leti have to begin with?

• 10+10=20

• 10-10=0

• 20+10=30

Sonia has 15 toys. She puts 8 of them on the self. How many does she have left?

Think about what fact family problems could you use to solve this problem.

Multiple Select

Sonia has 15 toys. She puts 8 of them on the self. How many does she have left?

Click on all the equation you can use to solve this problem.

• ?+8=15

• 15+8=?

• 15-8=?

• 8+15=?

Multiple Choice

Exit Ticket:

What is 13-9?

• 3

• 4

• 5

• 10