Transcript Homework Text page 117, #1

Do Now 11/21/11
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Take out HW from Friday.
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Copy HW in your planner.
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Text page 117, #1-5 all
Text page 114, #10-40 evens, #50
In your journal, solve the following problems. Explain how
the first problem is different from the rest.
 8 3
 8.2  3.5
6.1 18.7
5
 4.7
 12.6
 6.82(11.7)
79.794
8.16  3.4
2.4
Homework
Text page 117, #1-5 all
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1) 0.75 x $15.99 = $11.99
2) 5.5 – 1.4 = 4.1 feet
3) 15.3 – 0.8 – 1.12 = 13.38 seconds
4) Side C = 6 m, Side B = 12 m, and Side A = 14 m
5) Albert: 3.7 miles; Tryone: 1.2 miles;
altogether: 4.9 miles
Decimal Review
32.7 + (-62.82)
|32.7| = 32.7
|-62.82| = 62.82
62.82 – 32.7
Because 62.82 has a greater
absolute value than 32.7 the
answer is “negative”.
62.82
– 32.70
- 30.12
Use a zero as
a placeholder
so that both
numbers are
in the same
place value.
-5.23 – 9.1
Add the Opposite !!!
-5.23 + (-9.1)
To add two integers with the
SAME signs, find the sum of
their absolute values. Use the
sign of the two integers
5.23
+ 9.10
-14.33
Use a zero as
a placeholder
so that both
numbers are
in the same
place value.
Multiplying Decimals
 Find
the product.
3.06
x 1.4
1224
+306
4.284
4284
3.06 x 1.4
2 decimal places
1 decimal place
How many
decimal places
are in
each number?
How many
decimal places
are in the sum of
both numbers?
3 decimal places will then be in the product!
Find the quotient of -0.875 ÷ (-0.25)
0.25 0.875
Multiply both numbers
by 100 to make the
divisor an integer
35
25 87.5
75
12
125
Finished
25 87.5
Move the decimal point
straight up, then divide as
you normally would.
The quotient of two
integers with the same
sign is always
POSITIVE!
Objective
 SWBAT
solve equations using decimals
Equationmathematical
sentence
with an equal sign
Like a scale,
both sides
must be balanced
Section 3-4 “Solving Equations
Containing Decimals”
x + 7.2 = 10.5
Left side
‘x’ has to be 3.3 in
order to make the
equation balanced.
Like a scale, the left
side and right side must
be the same in order to
be balanced!
Right side
Solving Addition Equations…
Isolate the variable! Get ‘m’ by itself.
To get the ‘m’
by itself get rid of
“adding 4.7”
m + 4.7 = -18.2
– 4.7
-4.7
Do the opposite.
“Subtract 4.7”
Whatever you do to
one side of the equation
you must do the other side.
m = -22.9
Solving Subtraction Equations…
Isolate the variable! Get ‘y’ by itself.
To get the ‘y’
by itself get rid of
“subtracting 6.91”
Do the opposite.
“Add 6.91”
-2.26 = y – 6.91
+6.91
+6.91
4.65 = y
Whatever you do to
one side of the equation
you must do the other side.
Solving a Multiplication Equation
-0.6y = -5.1
-0.6
-0.6
y = 8.5
“Undo”
multiplication
by dividing
both sides of the
equation
Solving a Division Equation
-8· j = 1.75 · -8
-8
j = -14
“Undo”
division by
multiplying
both
sides of the
equation
Practice
s – 3.84 = 7.2
+ 3.84 + 3.84
s = 11.04
3.9 w = 1.2
3.9 x 3.9
w = 4.68
y + 20.51 = 26
-20.51 -20.51
y = 5.49
4 = 1.6c
1.6 1.6
2.5 = c
24
Homework
Text page 114, #10-40 evens, #50