Warm - Up
999 + 364 = (1000 +364) - 1 = 1363
Use a similar problem-solving
strategy to compute the
following. Show all of your
work.
Finished early?
1. 998 + 654
•Take out a colored writing
utensil and homework. Staple
2. 500-299
homework in order.
•Help a neighbor with these
3. 999+998
problems
1.2 & 1.4 Homework Check
Using your colored writing utensil, box in the following
two problems to be graded by a neighbor.
1.2 # 57) 15 – b, b = 7
1.4 # 27) 33 – 8 * 3 ÷12
Mathematical Properties
1.7-1.8
Pre-Algebra Properties
Property
1. Commutative
Property of
Addition
In words…
You can add
terms in any
order
In math…
2+3 = 3+2
2. Commutative You can multiply 3 ∙ 7 = 7 ∙ 3
terms in any
Property of
order
Multiplication
Pre-Algebra Properties
In words…
Property
In math…
3. Associative Changing the grouping (9+5)+6 =
of terms does not
Property of
9+(5+6)
change the sum
Addition
4. Associative Changing the grouping (5∙10) ∙ 3 =
of terms does not
Property of
5 ∙(10 ∙ 3)
Multiplication change the product
Pre-Algebra Properties
In words…
Property
Multiply a number in
5. Distributive
front of
Property
parentheses to all
terms inside the
parentheses
In math…
5(x+2)
=5∙x + 5∙2
=5x+10
Name this property!
7∙8=8∙7
Commutative Property of Multiplication
Name this property!
(2+3)+4 = 2+(3+4)
Associative Property of Addition
Name this property!
2(x+3) = 2x + 6
Distributive Property
Name this property!
(2)(3)(4) = (3)(2)(4)
Commutative Property of Multiplication
Name this property!
(2+3) + 4 = (3+2) + 4
Commutative Property of Addition
Using the Distributive Property
Now let’s try to reverse the distributive
property!
5 ( ___
n + ___)
3
5n + 15 = ___
Think! What number was distributed to
give us 5n and 15?
Using the Distributive Property
Now let’s try to reverse the distributive
property!
7
1 + ___)
2x
7 + 14x = ___
( ___
Think! What number was distributed to
give us 7 and 14x?