standard_description: Apply properties of operations as strategies to add and subtract. (Students need not use formal terms for these properties.) Examples: If 8 + 3 = 11 is known, then 3 + 8 = 11 is also known. (Commutative property of addition.) To add 2 + 6 + 4, the second two numbers can be added to make a ten, so 2 + 6 + 4 = 2 + 10 = 12. (Associative property of addition.)
problem_activity: Problem 1
Point
A
is located at
$$-4.5$$
, and point
B
is
$$3.25$$
units from point
A
. Write two addition equations that could be used to determine the location of point
B
. Model this on the number line below.
[IMG]
Problem 2
Find the sums.
a.
$${-3+ \left (-2 {1\over4} \right )}$$
b.
$${5.7 + (-12.2)}$$
c.
$${-9 + 3 {2\over5}}$$
d.
$${-{10\over3} + 18}$$
e.
$${-2+3+(-1)+5}$$


aligns: no