Addition Properties
What is the missing number and property of addition?
3
Associative Property
If you have the number : 3, 417 what is 10 more and 100 more?
10 more: 3,427
100 more: 3,517
Take apart the addends to add mentally
151= 100 + 50 +1
128 = 100 + 20 + 8
200+70+9= 279 seats
Sammy is trying to find out about how many tickets were sold to a football game. There were 247 student tickets sold. There were 142 non-student tickets sold. The football coach asked Sammy to round each addend to the nearest 10 before adding mentally.
247 to the nearest 10: 250
142 to the nearest 10: 140
250 + 140 = 390 tickets
A bookstore sells 584 books on Monday. The bookstore sells 337 books on Tuesday. How many books were sold in all?
584 + 337 = 921
Sid has 4 blue pens and 5 red pens. Mario has 5 blue pens and 4 red pens. How many pens does each boy have?
What property of addition is this an example of?
4+5=9
5+4=9
Commutative Property
Mrs. Kelly writes a list of numbers on the board. She asks the class to find the number that would complete the pattern. What is the pattern?
6,942; 6,952; 6,962; ___________ ; 6,982; 6,992
The number pattern is ___________________.
6,972
The number pattern is add 10.
134 + 99 = ____
Make 100 to make it easier to add
134-1 = 133
99+1= 100
133+100= 233
So 134+99=233
Estimate the sum. Round to the greatest place value
534 + 89 = ____
534 rounded to nearest 100: 500
89 to nearest 10: 90
500 + 90 = 590
During a weekend trip to Vermont, the Wildlife Club saw 127 wrens and 58 eagles. How many wrens and eagles did the Wildlife Club see?
Estimate 127+58
Then check for reasonableness
130 + 60 = 190
127 + 58 = 185
Anna practice the piano for 3 hours on Friday. She did not practice at all on Saturday. How many hours did she practice altogether?
What property of addition is this an example of?
3+0=3
0+3=3
Identity Property
Lewis kept track of the miles his family traveled on a trip. Each time they stopped, he wrote down the miles from the odometer. Lewis noticed a pattern in the numbers he wrote. Describe the pattern.
9,674; 9,774; 9,874; ________
What is the next number in the pattern?
9,974
Each time they stopped they had traveled 100 miles.
There are 37 boy students and 25 girl students on the bus. How many students are on the bus? Use mental math to find 37 + 25.
37-5 = 32
25 + 5= 30
32+30=62
so 37+25=62
There are 62 students on the bus.
The Board Shop sold 342 snowboards and 637 pairs of boots in the last year. About how many snowboards and pairs of boots did they sell altogether?
Round to the nearest 100 and then add.
300 + 600 = 900
164 + 17 = ______
181
(2+5) + 8 = ____
2 + (5+8) = _____
What property of addition is this an example of?
2 + (5+8) = 15
Associative Property
100 more than 3,728
3,828
Make a ten to add mentally
64 + 8 = _____
64 -2 = 62
8 + 2 = 10
62 + 10 = 72
so 64 + 8 = 72
Round to the greatest place value and then add.
200 + 700 = 900 visitors
3,782 + 1,747 = ____________
5,526
Mrs. Jackson bought 3 blue notebooks and 9 red notebooks. Mr. Mendez bought 9 blue notebooks and 3 red notebooks. How many notebooks did they each buy?
What property of addition is this an example of?
Mrs. Jackson: 3+9=12
Mr. Mendez: 9+3=12
Commutative Property
9,995
Make a ten to add mentally
539 + 356 = ______
539 + 1 = 540
356 - 1 = 355
540 + 355 = 895
so 539 + 356 = 895
Round to the nearest 10 and add
383 + 122 = _____
Round to the nearest 100 and add
383 + 122 = ______
390 + 120 = 510
400 + 100 = 500
The largest cruise ship can carry 1,365 crew members and 4,376 passengers. What is the total number of passengers and crew that can travel on the cruise ship?
Estimate to find 1,365 + 4,376. Check for reasonableness.
1,400 + 4,400 = 5,800
1,365 + 4,376 = 5,741