15 terms

LCS 4th Math ch. 2 Addition and Subtraction Problems

STUDY
PLAY
commutative property of addition
numbers can switch places and the sum stays the same
associative property of addition
how numbers are grouped doesn't matter and the sum stays the same
identity property of addition
sum of any number and zero is that number
subtraction rule of zero a
number minus itself equals zero
subtraction rule of zero b
number minus zero equals itself
commutative example
8+5=5+8
associative example
(8+9)+3=8+(9+3)
identity example
81+0=81
subtraction rule a example
9-9=0
subtraction rule b example
8-0=8
about means
estimate
estimate
round the numbers then solve
round
solve then round the answer
check addition by
estimating
check subtraction by
adding