Addition Properties
What property of addition is being used here?
(2+5)+8=
2+(5+8)=
Associative
Add. Show your work.
445+26
445+26=471
What place (thousands, hundreds, tens, or ones) lines up when we add 4 digit numbers vertically?
Ones place
Estimate. Round to the nearest ten.
34+23
30+20=50
What is 10 more than 1,465?
1,475
What property of addition is being used here?
2+8=
8+2=
Commutative
Find the unknown
607+27=?
The unknown is 634
Add. Show your work
8,285+1,456
8285+1456=9,741
What key word in a word problem tells us we need to estimate a sum?
About
What is 100 more than 8,699?
8,799
What property of addition is being used here?
100+0=
Identity
Add. Check for reasonableness.
597+51
597+51=648
Round to tens to estimate
600+50=650
Add. Check for reasonableness by rounding to the hundreds place.
5,555+3,555
5,555+3,555=9110
5,600+3,600=9,200
What makes an estimated sum reasonable? (2 part answer)
It makes sense. It is close to the real sum.
3,400; 3,500; 3,600;_____
3,700
What addition property can we use to compete this sentence?
6+__=6
Identity
Add. Show your work. Use the commutative property to check for accuracy.
231+596
231+596=827
596+231=827
Add to find the unkown.
2,865+5,522=?
2,865+5,522=8,387
Estimate. Round each addend to the nearest ten AND the nearest hundred.
133+560=
130+560=690
100+600=700
Identify the pattern.
4,720; 4,730; 4,740; 4,750
Add ten
Kelly collected 16 postcards last summer. This summer she did not collect any postcards. How many postcards did she collect all together? Which property did you use to find your answer?
16, identity
A 10 speed bike is on sale for $199, and a 12 speed racing bike is on sale for $458. How much do the two bikes cost all together? Show your work.
199+458=657
Add. use the commutative property to check for accuracy. Show your work.
1,734+2,882
1,734+2,882=4,616
2,882+1,734=4,616
A high school gymnasium can seat 2,136 people. To the nearest ten and hundred, about how many people can sit in the gymnasium? Which estimate is closer? Explain.
Nearest ten = 2,140
Nearest hundred = 2,100
Tens is closer because 2,136 is closer to 2,140
A baby elephant weighed 264 pounds at birth. It gained 100 pounds each month. How much does the elephant weigh in 4 months?
At birth: 264 pounds
Month 1: 364
Month 2: 464
Month 3: 564
Month 4: 664