Addition Strategies & Identity Property
What are the numbers added together in an addition problem called?
Addends
What is the answer to a subtraction problem called?
The Difference
When parentheses are used what is the first step in an addition equation?
(7 + 3) + 4 = 7 + (3 + 4) =
Add the numbers that are in the parentheses first.
(7 + 3) + 4 = 14 7 + (3 +4) = 14
(10) + 4 = 14 7 + (7) = 14
Use the Commutative Property to write the related addition fact
5 + 6 = ?
5 + 6 = 11 6 + 5 = 11
Subtract these two equations
8 - 6 = 12 - 9 =
8 - 6 = 2 12 - 9 = 3
Write the fact families 7 8 15
7 + 8 = 15 8 + 7 = 15
15 - 7 = 8 15 - 8 = 7
What is the answer in an addition problem called?
Sum
In subtraction we count backwards. What counting strategy can you use to find the difference between 8 & 1 OR 8 - 1 =
count back 1
answer = 7
What is the principal of addition called when parentheses are used in the equation
Grouping Principal of Addition
Write each Fact Family for 2, 9 & 11
(2 + 9 = 11)
(9 + 2 = 11)
(11 - 2 =9)
(11 - 9 =2)
Write the fact families 7 7 14
7 + 7 = 14 14 - 7 = 7
Write + or - to complete each equation
6 ___ 9 = 15 16 ____ 8 = 8
6 + 9 = 15 16 - 8 = 8
Near Doubles
6 + 7 =
13
Subtract All Strategy
8 - 8 =
The answer is always 0
Add by going down. 9
1
+ 4 =
14
Solve the missing addend by thinking of the related subtraction fact 5 + n = 12
12 - 5 = 7
5 + 7 = 12
n = 7
Write the fact families 6 7 13
6 + 7 =13 7 + 6 = 13
13 - 7 = 6 13 - 6 = 7
Ms. Nicky placed 7 cookies on a plate for class. She put the rest of the cookies back in the box. Ms. Nicky had a total of 16 cookies altogether. How many cookies did Ms. Nicky put back into the box.
7 + n = 16 16 - 7 = 9 7 + 9 = 16
n = 9 9 cookies went back into the box
Adding 9
3 + 9 =
12
Count Back 2 Strategy
7 - 2 =
Think: 7, 6, 5
answer: 5
Which 2 numbers that make 10. Add and solve 6
3
4
+ 2=
6 & 4 make 10 total = 15
Write + or - to complete the equation 12 9 = 3
12 - 9 = 3
14 - 5 = 9 5 + 9 = 14 n = 9
Write the letter that names the number
A. fifty __40
B. Twenty __ 30
C. Forty __ 50
D. Ten __ 20
E. Thirty __ 10
C - 40
E - 30
A - 50
B - 20
D - 10
Identity Property of Addition definition or equation
When 0 is an addend, the sum(answer) is the same as the other addend.
8 + 0 = 8
Zero Property of Subtraction definition or equation
When 0 is subtracted from a number, the answer is always that same number
9 - 0 = 9
Associative Property Definition or equation
The grouping of addends can be changed without changing the sum
(7 +3) + 4 = 14 7 + (3 + 4) = 14
Commutative Property of Addition definition or equation
The order of the addends can be changed without changing the sum.
7 + 8 = 15 8 + 7 = 15
Read the clues and write the number:
6 is in the tens place
4 is in the Ones place
3 is in the Hundreds place
364
Soreniti gave 7 bibles to Luke to hand out to the children during Bible class. Luke already had 4 bibles in his hand. How many total bibles did Luke pass out.
What equation we would us to solve this problem and what is the answer
7 + 4 = 11
Luke passed out 11 bibles total