Addition Properties
This property says that numbers can be added in any order.
Commutative Property
What are the steps to finding an estimate to an addition problem?
1. Round
2. Add
416
+ 362
778
289
- 145
144
Mallory flew two round trips. They were 3,720 miles and 5,985 miles. Which is the best estimate of the total distance Mallory flew?
a) 11,000 miles
b) 9,700 miles
c) 8,700 miles
d) 8,000 miles
b) 9,700
This property says that numbers can be regrouped in an addition problem without changing the value.
Associative Property
Round to the largest place value:
456,912
500,000
8,818 + 1,182 =
10,000
683
- 295
388
A Little League team played a doubleheader (2 back to back games). The first game lasted 155 minutes. The second game lasted 175 minutes. There was a 30 minute break between the games. What was the total time of both games plus the break?
360 minutes OR 6 hours
This property says that adding zero to a number doesn't change the value.
Identity Property
Estimate the sum:
6,219
+ 4,811
6,219 --> 6,000 6,219--> 6,200
+4,811 --> + 5,000 +4,811--> +4,800
11,000 11,000
30,080
+19,187
49,267
9,128
- 3,753
5,375
Maria added 45,273 and 35,687 and got a sum of 70,960. Is her answer reasonable? Explain.
No.
45,273 + 35,687 is about
45,000 + 36,000 = 81,000
Maria's sum is not close to 81,000
Which property is being used?
3,371 + 2,429 = 3,371 + (29 + 2,400)
= (3,371 + 29) + 2,400
= 3,400 + 2,400 = 5,800
Associative Property
Estimate the sum:
823,725
+ 44,851
823,725 --> 820,000
+ 44,851 --> + 40,000
860,000
72,438
+ 6,854
79,292
215,714
- 176,313
39,401
Hernando County is 473 square miles.
Union County is 244 square miles.
How much greater is the area of Hernando County than Union County?
229 square miles
Which properties are being used? (There are 2!)
92,425 + 31,675 =
+75 -75 =
92,500 + 31,600 =
90,000 + 30,000 + 600 + 500 = 124,100
Identity Property
Commutative Property
Estimate the difference:
1,440
- 933
17,586 --> 18,000 or 20,000
- 9,483 --> - 9,000 - 9,000
9,000 11,000
29,634 + 12,958 + 6,835 =
49,427
30,900
- 22,855
8,045
A crayon company makes 87,491 blue crayons, 36,262 red crayons, and 25,063 gray crayons. How many more blue crayons are made than red and gray combined?
26,166 more blue crayons
red plus gray -> 36,262+25,063=61,325
blue minus (red + gray) -> 87,491 - 61,325 =26,166