Transcript subtraction - SCHOOLinSITES

Beginning
Algebra
Applications using Subtraction
Applications Using Subtraction
Objective 2. To simplify expressions containing subtraction
using the rule for order of operations.
Objective 3. To translate sentences from English into
symbols then simplify.
Objective 4. To find the complement and supplement of
an angle.
Applications Using Subtraction
Translate sentences from English
into symbols then simplify.
1. Subtract -5 from 13.
2. Subtract -3 from the sum of 9 and 7.
3. What number do you subtract from 2
to get 8?
Translating English phrases and sentences:
1.
Subtract - 5 from 13.
Put negative numbers in ( )
The object of the preposition “from” comes first.
13 – (- 5)
add opposite
13 + 5 = 18
Translating English phrases and sentences:
2. Subtract -3 from the sum of 9 and 7.
Put negative numbers in ( )
Write the object of the preposition “of ” in ( 9 + 7)
Subtract (-3) from the sum
(9 + 7).
The object of the preposition “from” (9 + 7) comes first.
( 9 + 7) – (- 3) add opposite
16 + 3 = 19
Translating English phrases and sentences:
3. What number do you subtract from -2 to get 8?
Put negative numbers in ( )
 Subtract n from (- 2) to get 8
=
The object of the preposition “from” (- 2) comes first.
( - 2) – n = 8
add opposite
add opposites to both sides
( - 2) + (-n) = 8
 n = - 10
( - 2) + ( - 8) = n
Check:
( - 2) - (-10) = 8
or
( - 2) + (10) = 8
GEOMETRY
Circles have 360o around the Center

360
The number of degrees swept out by the radius
as it rotates once around the circle is 360.
The number of degrees in a circle is 360.
GEOMETRY
Complementary and Supplementary Angles
The number of degrees in a square angle
is 90 and two angles whose sum is 90
are called complementary. (A & B)
Complement:
B = 90 – A
The number of degrees on a straight angle
is 180 and two angles whose sum is 180
are called supplementary. (C & D)
Supplement:
D = 180 – C
A
B
A + B = 90
C
D
C + D = 180
GEOMETRY
Complementary and Supplementary Angles
A square angle has 90 so x + 30 = 90
x
30
Use subtraction: x = 90 - 30 or x = 60
A straight angle has 180 so x + 130 =180
x
130
Use subtraction: x = 180 - 130 or x = 50
Translating English Sentences:
In algebra subtraction is “adding the opposite” not
“taking away”. In arithmetic the result is a positive number,
sometimes it is small and sometimes large, but in algebra
the result can also be a negative number with a small or
large absolute value.
All operations are performed by particular and exact
properties.
Some Words that imply subtraction:
Minus, Less, Less than, Difference, Decrease,
Lose, Has dropped (temperature), Depreciated
by, Withdrawal, Distance, length comparison
(shorter, longer) …
Translating English Sentences:
Problem Involving Subtraction
The Weather Channel announced that a cold front had
come through the area. At noon the temperature was at a
high of 82F. By 3:00 pm the temperature had dropped
17F and by 6:00 pm it had dropped another 12F. Write an
expression to indicate the temperature changes and find the
temperature at 6 pm.
(82 – 17) – 12
65 – 12 = 53
The temperature at 6 pm was 53F
Translating English Sentences:
Problem Involving Subtraction
Depreciation: A computer that costs $5225 has a
value of $4075 after one year.
a) How much less is this value?
Depreciation means to find the difference in the values.
Difference = $5225 – $4075 = $1150
The original value of the computer depreciated
by the amount of $1150 in the first year.
Translating English Sentences:
Problem Involving Subtraction
The original value of the computer depreciated
by the amount of $1150 in each of the first four
years.
Write a sequence of numbers that gives the
value of the computer system at the beginning of
each of the first four years.
Can this sequence be considered an arithmetic sequence?
Yes, it has a common difference: - $1,150)
Problem Involving Subtraction
b) The sequence for each of the first four years.
Year:
1
Value:
$5,225
2
$5,225
– $1,150
Sequence:
$5,225
$4,075
3
4
$5,225
$5,225
– $1,1502
$2,925
– $1,1503
$1,775
THE
END