Adding and Subtracting Within 20

Add to 20

What is your favorite addition strategy?

Objectives

Students will:

• Review a chart of addition strategies

• Answer opinion based questions to decide which strategy works the best for you

• Work through addition equations using several addition strategies

Poll

How do you feel about adding to 20? (example: 12 + 8 = ?)

• I feel great!

• I think I can do it!

• It's a little tricky!

• I don't understand it!

Learning Target

• I can explain how addition and subtraction are related.

• I can identify number sentences in a fact family.

What is a a fact family?

• A group of related addition and subtraction facts using the same numbers

Multiple Select

Which facts go with this fact family? 7, 3, 4

• 3 + 4 = 7

• 7 + 3 = 10

• 7 - 3 = 4

• 7 - 4 = 3

I have a question...

• Why isn't 3 + 7 = 10 in this fact family?

Multiple Select

Which number sentences go with this fact family? 8, 6, 2

• 8 + 6 = 14

• 6 + 2 = 8

• 8 - 6 = 2

• 2 - 8 = 6

I have a question...

• Why isn't 2 - 8 = 6 in this fact family?

Fill in the Blanks

Multiple Choice

Which number sentences DOES NOT fit in this fact family? 8, 5, 3

• 3 + 5 = 8

• 5 + 3 = 8

• 8 + 3 = 11

• 8 - 3 = 5

Multiple Select

Select all the number models that relate to this fact family.

• 7 + 5 = 12

• 12 - 7 = 5

• 12 + 7 = 5

• 7 - 5 = 12

• 12 - 5 = 7

Multiple Select

Select all the number models that relate to this fact family.

• 8 + 2 = 10

• 2 + 6 = 8

• 6 + 2 = 8

• 2 + 8 = 6

• 2 = 8 - 6

Multiple Select

Select all the number models that relate to this fact family.

• 8 = 14 - 6

• 6 + 8 = 14

• 6 = 8 - 14

• 2 + 8 = 14

• 14 = 8 - 6

Multiple Select

Select all the number models that relate to this fact family.

• 9 = 15 - 6

• 6 = 15 - 9

• 6 + 9 = 15

• 6 - 9 = 15

• 15 = 9 - 6

Multiple Choice

Finish this fact family.
2+8=10
8+2=10
10-2=8

• 10-5=5
• 8-2=10
• 10-8=2
• 8-10=2

Multiple Choice

Which fact is missing from this fact family?
7+7=14

• 14-7=7
• 14+7=21
• 7+14=21
• 7-14=7

Multiple Choice

Which fact completes this fact family?
9+1=10
10-1=9
10-9=1

• 1+10=10
• 10+0=10
• 1+9=10
• 10+9=19

Multiple Choice

Which fact completes this fact family?
12+7=19
7+12=19
19-12=7

• 7+2=9
• 19+7=26
• 7+19=26
• 19-7=12