Transcript Presentation

Study your factors
and multiples
(LCM and GCF).
Evaluate the sum
1. 4.12 + 09.2
2. 132.27 + 29
Add & Subtract Decimals
Standard:
MCC6.NS3 The Number System
Fluently add, subtract, multiply and
divide multi-digit decimals using the
standard algorithm for each operation.
I Can:
 Estimate the sum and difference with
decimals.
 Add and subtract decimals
TIPS for adding and subtracting decimals
1. First, line up the decimals.
2. Add or subtract from right
to left. Regroup if necessary.
3. Bring the decimal straight
down in your answer.
Adding
Examples:
4.55 + 11.3
You can add
a zero to
help keep
everything
lined up
Line up the
04.55
+ 11.30
15.85
Put the first
number on the top
of the second
number and line
up the decimals.
When adding
or subtracting
you always
start from the
right and work
left.
Subtracting
Examples:
15.55 - 4.3
You can add
a zero to
help keep
everything
lined up
Line up the
-
15.55
4.30
11 .25
Put the biggest
number on the top
of the second
number and line
up the decimals.
When adding
or subtracting
you always
start from the
right and work
left.
1) 0.3 + 0.05 =
2) 7. 5 + 4 =
3) 0.06 + 0.001
=
4) 0.2 + 3 =
5) 0.006 + 0.4
=
1)
2)
3)
4)
5)
10.0 - 0.4 =
7.8 - 0.9 =
0.25 - 0.03=
3.3 - 0.05 =
4.3 - 0.03 =
1. 23.4 + 1.46
2. 12.32 - 1.5
Solve the sum or
difference
24.516 – 5.25
2.784 + 45. 2
Some SCIS 6th graders went to a math
competition. Devon completed 20
problems in 12.6 seconds. Trent completed
20 problems in 15.2 seconds.
1. What is the difference in Devon and
Trent’s time?
2. What is Devon and Trent’s time
collectively.
Be sure you receive a
handout. Glue it to your
homework page for the
week.
One event in competitive swimming is the
women’s 100-meter butterfly. The table shows
the times of different swimmers at a recent
Olympics.
Swimmer’s
Time (s)
Brittany
Markayla
Jasmine
56.73
?
58.10
It took Markayla 0.37
seconds longer to finish
than Brittany. What was
Markayla’s time , in
seconds?
At a SCIS meet, a swimmer
swam the women’s 100-meter
butterfly in 45.34 seconds.
How many seconds faster did
Jasmine swim her race?
Swimmer’s
Time (s)
Brittany
Markayla
Jasmine
56.73
?
58.10
At a SCIS meet, a swimmer
It took Markayla 0.37
seconds longer to finish swam the women’s 100-meter
than Brittany. What was butterfly in 45.34 seconds.
How many seconds faster/
Markayla’s time , in
did Jasmine swim her race
seconds?
+
Tens
Ones
5
6
7
3
0
3
7
7
1
0
5
Tenths Hundredths
-
Ten Ones Tenths Hundredths
s
5
8
1
0
4
5
3
4
1
2
7
6
You
Try
1.
42
2.
12
x
x
1.
54 2. 2.2
x 4
x 1.2
Multiply & Divide Decimals
Standard:
MCC6.NS3 The Number System Fluently add,
subtract, multiply and divide multi-digit decimals
using the standard algorithm for each operation.
I Can:
 Multiply decimals by whole numbers.
 Multiply two decimals
 Estimate the product of decimals.
Multiplying Decimals
1.When multiplying a decimal by a
decimal, multiply as whole
numbers.
2.To place the decimal point, find
the sum of the number of
decimal places in each factor.
3.The product has the same
number of decimal places.
Multiplying Decimals
•For example: Find 4.2 x 6.7
4.2 One decimal place
x 6.7 One decimal place
294
252
28.14 Two decimal places
The product is 28.14.
Example: 5.63 x 3.7
4 2
5.63
x 3.7
39 4 1
+ 168 9 0
20.8 31
5.63
x 3.7
two
one
1 1
1
three
Dividing Decimals
“Swingin’ Monkeys”
Swinging Monkeys!
Follow these steps and you will
be great at dividing decimals!
Remember: Whatever the
OUTSIDE monkeys do – the
INSIDE monkeys do also!
Division Vocabulary
.2 12.64
“Outside”
Divisor
“Inside”
Dividend
“Roof”
Quotient
Division Vocabulary
12.64 ÷ .2
12.64 divided by .2
.2 12.64
Steps in Dividing Decimals
1.Make the divisor (outside number) a whole
number by moving (swingin’) the decimal to the
right as many places as it takes to make it a
WHOLE NUMBER.
2.In MONKEY TERMS: Whatever the outside
monkey does (how far it swings) the inside
monkey does also. Then the monkey climbs up
and sits on the roof!
Swingin’ Monkeys
Divisor
.2 12.64
Moved
(swung) the
decimal
point 1
place to the
right
Steps in Dividing Decimals
2. Move (swing) the decimal point in the
dividend the same number of places as
the divisor.
.2 12.64
Moved (swung)
the decimal
point 1 place to
the right
Dividend
Steps in Dividing Decimals – Swingin’
Monkeys
3. Place (swing) the decimal point in the
answer (quotient) lined up with the
decimal point in the dividend (on the
roof).
2. 126.4
Steps in Dividing
Decimals
4. Now, divide as usual!
2 126.4
Steps in Dividing Decimals
4. Divide the numbers. Make sure
the decimal point stays lined up.
63 2
2 126.4
12
6
6
4
1.
2.15 x
5.4
2.
24 ÷
1. Find the product
12.54 X 2.3
2. Find the quotient
1.530 ÷ 0.5
Let’s Practice
Remember: The more
neatly you write and
keep the numbers lined
up, the BETTER!
Lets Practice
Together
1)14.2 ÷ 0.2 =
2)25.5 ÷ 1.5 =
You Try
1) 0.12 ÷ 24.12
=
2)
0.9 ÷ .972 =
More Practice
1) 42.0 ÷ 0.3
2) 14.56 ÷ 2.8
3) 5.28 ÷ 4.8
1. 1.75 x 4.6
2. 0.54 ÷ 0.03
3. 45.246 + 15.4
4. 74.154 – 6.54