Addition Properties
What are the names of the three addition properties?
Commutative, Associative, Identity
What does it mean to estimate?
Make a close guess - find a number close to the exact number.
When adding 3-digit numbers, what must line up?
Place values
When adding 4-digit numbers, what must line up?
Place values
Which property states that the sum of any number and zero is the number?
5+0=5
Identity
Estimate. Round each number to the indicated place value:
34+23; tens
30+20=50
Line numbers up and add on white board:
759+19=
778
Line numbers up and add on white board:
8,285+1,456=
9,741
Which property states that the order in which numbers were added did not change the sum?
3+5=8 5+3=8
Commutative
Estimate. Round each number to the indicated place value:
1,172+1,115; tens
1170+1120=2290
Line numbers up and add on white board:
597+51=
648
Line numbers up and add on white board:
3,075+5,640=
8,715
Which property states that the way in which the addends are grouped does not change the sum?
(9+4)+6=9+(4+6)
Associative
Estimate. Round each number to the indicated place value:
687+231; hundreds
700+200=900
Line numbers up and add on white board:
231+596=
827
Line numbers up and add on white board:
2,333+5,977=
8,310
What are the things that group operations called?
(____)
Parenthesis
Estimate. Round each number to the indicated place value:
4,412+1,204; hundreds
4,400+1,200=5,600
Line numbers up and add on white board:
173+591=
764
Line numbers up and add on white board:
2,311+2,862=
5,173