1st_MA_NS_2.1_SUBTRACT_NUMBER_FACTS_TO_TEN
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Transcript 1st_MA_NS_2.1_SUBTRACT_NUMBER_FACTS_TO_TEN
Learning Objective
Name _____________________________
Today, we will subtract numbers.
CFU
What are we going to do today?
Today, we are going to subtract numbers.
What are we going to subtract? We are going to subtract numbers.
Activate (or Provide) Prior Knowledge
Students hold up one hand and count your fingers.
How many fingers did you count?
Now put one finger down and count how many fingers are left up.
How many fingers did you count?
CFU
Teacher models first, then students.
Students, you already know we can take things away. We can do the same thing with numbers. This is
called subtraction. Today, we will subtract numbers.
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© 2011 All rights reserved.
Comments? [email protected]
1st Grade Number Sense 2.1
Know the addition facts (sums to 20) and the corresponding subtraction
facts and commit them to memory.
Lessons are to be used by EDI-trained teachers only.
Concept Development
To subtract means to take away.
The “- ” sign is called the “minus” sign. It tells us to subtract the numbers.
The = sign stands for equals.
Example:
There are 3 slices of pizza. If Billy eats 1 slice how many slices of pizza
are left?
3
1
=
2
We say, “Three minus one equals two.”
1 slice of pizza subtracted from 3 slices of pizza equals 2 slices left over.
CFU What does subtract mean? To subtract means to
____________.
take away.
What is it called when we take away numbers? ______________.
Subtract
Which numbers are subtracted correctly?
A. 2 – 1 = 3
–
B. 2 – 1 = 1
=
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© 2011 All rights reserved.
Comments? [email protected]
–
=
1st Grade Number Sense 2.1
Know the addition facts (sums to 20) and the corresponding subtraction
facts and commit them to memory.
Lessons are to be used by EDI-trained teachers only.
Importance
To subtract means to take away.
It is important to be able to subtract numbers so you can:
1. count faster.
2. know how many objects are left over.
4 pieces
I eat
1
I have
3 left
4 -1 = 3
CFU
Does anyone else have another reason why it is important to be able to subtract numbers? (pair-share) Why is it important to be able to
subtract numbers? You may give me one of my reasons or one of your own. Which reason means more to you? Why?
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
© 2011 All rights reserved.
Comments? [email protected]
1st Grade Number Sense 2.1
Know the addition facts (sums to 20) and the corresponding subtraction
facts and commit them to memory.
Lessons are to be used by EDI-trained teachers only.
Name________________________
Skill Development/Guided Practice
My Subtraction Facts for 1, 2, and 3
Step #1: Find the first number of the
subtraction fact on the number line.
Step #2: Read the second number.
a. Subtract by counting down this
many times.
Step #3: Read the fact aloud.
0
1
2
2
- 1
2
- 2
0
1
0
2
- 0
3
- 1
2
2
1
- 1
3
4
5
6
7
8
9 10
3
- 2
1
- 0
1
1
2
- 1
3
- 0
3
- 3
1
3
0
1 - 0 ____
1
1 - 1 ____
0
2 - 0 ____
2
2 - 1 ____
1
2 - 2 ____
0
3 - 0 ____
3
3 - 1 ____
2
3 - 2 ____
1
3 - 3 ____
0
2 - 0 ____
2
CFU How did I know where the first number was on the number line? How did I subtract using the second number?
How did you know where the first number was on the number line? How did you subtract using the second number?
1st Grade Number Sense 2.1
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
© 2011 All rights reserved.
Comments? [email protected]
Know the addition facts (sums to 20) and the corresponding subtraction
facts and commit them to memory.
Lessons are to be used by EDI-trained teachers only.
Name________________________
Skill Development/Guided Practice (continued)
My Subtraction Facts for 4, 5, and 6
Step #1: Find the first number of the
subtraction fact on the number line.
Step #2: Read the second number.
a. Subtract by counting down this
many times.
Step #3: Read the fact aloud.
0
1
2
3
4
5
6
7
8
9 10
5
- 5
6
- 4
5
- 4
6
- 3
1
0
2
1
3
5
- 3
4
- 4
4
- 3
6
- 2
5
- 2
2
0
1
4
3
6
- 5
6 - 1 ____
5
4 - 2 ____
2
6 - 6 ____
0
4 - 1 ____
3
6 - 0 ____
6
5 - 0 ____
5
6 - 4 ____
2
5 - 1 ____
4
4 - 0 ____
4
5 - 2 ____
3
CFU How did I know where the first number was on the number line? How did I subtract using the second number?
How did you know where the first number was on the number line? How did you subtract using the second number?
1st Grade Number Sense 2.1
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
© 2011 All rights reserved.
Comments? [email protected]
Know the addition facts (sums to 20) and the corresponding subtraction
facts and commit them to memory.
Lessons are to be used by EDI-trained teachers only.
Name________________________
Skill Development/Guided Practice (continued)
My Subtraction Facts for 7 and 8
Step #1: Find the first number of the
subtraction fact on the number line.
Step #2: Read the second number.
a. Subtract by counting down this
many times.
Step #3: Read the fact aloud.
0
1
2
3
4
5
6
7
8
9 10
7
- 7
8
- 6
7
- 6
8
- 5
1
0
2
1
3
7
- 5
8
- 4
7
- 4
8
- 3
7
- 3
2
4
3
5
4
8
- 7
8 - 2 ____
6
7 - 2 ____
5
8 - 1 ____
7
7 - 1 ____
6
8 - 0 ____
8
7 - 0 ____
7
0
8 - 8 ____
8 - 2 ____
6
7 - 6 ____
1
7 - 5 ____
2
CFU How did I know where the first number was on the number line? How did I subtract using the second number?
How did you know where the first number was on the number line? How did you subtract using the second number?
1st Grade Number Sense 2.1
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
© 2011 All rights reserved.
Comments? [email protected]
Know the addition facts (sums to 20) and the corresponding subtraction
facts and commit them to memory.
Lessons are to be used by EDI-trained teachers only.
Name________________________
Skill Development/Guided Practice (continued)
My Subtraction Facts for 9 and 10
Step #1: Find the first number of the
subtraction fact on the number line.
Step #2: Read the second number.
a. Subtract by counting down this
many times.
Step #3: Read the fact aloud.
0
1
2
3
4
5
6
7
8
9 10
9
- 9
10
- 8
9
- 8
10
- 7
1
0
2
1
3
9
- 7
10
- 6
9
- 6
10
- 5
9
- 5
2
4
3
5
4
10
- 9
10 - 4 ____
6
9 - 4 ____
5
10 - 3 ____
7
9 - 3 ____
6
10 - 10 0
___
10 - 2 ____
8
9 - 2 ____
7
10 - 1 ____
9
9 - 1 ____
8
9 - 0 ____
9
CFU How did I know where the first number was on the number line? How did I subtract using the second number?
How did you know where the first number was on the number line? How did you subtract using the second number?
1st Grade Number Sense 2.1
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
© 2011 All rights reserved.
Comments? [email protected]
Know the addition facts (sums to 20) and the corresponding subtraction
facts and commit them to memory.
Lessons are to be used by EDI-trained teachers only.
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DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
© 2011 All rights reserved.
Comments? [email protected]
1st Grade Number Sense 2.1
Know the addition facts (sums to 20) and the corresponding subtraction
facts and commit them to memory.
Lessons are to be used by EDI-trained teachers only.