3rd Grade Math Skills

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3rd GradeMath Skills Strategies
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Problem of the Day Strategies

• Find (Identify the question)
• Know (Gather Information)
• Strategies
• Draw a picture
• Make an organized list
• Make a table
• Make a graph
• Act it out
• Look for a pattern
• Try, check, revise
• Write an equation
• Use reasoning ? ALWAYS!! ?
• Work backwards
• Solve a simpler problem

4. Show the problem (work it out) 5. Solution
(the answer to the problem) 6. Answer (in a
complete sentence) 7. Check for reasonableness,
evaluate (do the opposite add/subtract,
multiply/divide, etc.)
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Word Problem Strategies

1. Read the word problem.
2. Find and underline the question.
3. Box out key words vocabulary words.
4. Circle numbers you need, underline labels, mark
   out any distractors.
5. Choose your strategy.
6. Solve the problem (show your work!)
7. Prove your answer.

• If labels are the same
• ADD or SUBTRACT!
• If labels are different
• MULTIPLY or DIVIDE!

• Watch for 2-step problems!
• Watch for EXTRA or MISSING information!
• Check answer for reasonableness!

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Place Value
Standard Number Form 43,621 Word Form
Forty-three thousand, six hundred
twenty-one Expanded Notation 40,000 3,000
600 20 1 Pizza Place Value 43,621 (line
the numbers up correctly and it will
40,000 look like a slice of pizza!)
3,000 600 20
1 HTO Chart 100TH 10TH TH H T
O 4 3 6 2
1 Digit Number Value The worth of something.

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Patterns
A B C A
____
Repeating Pattern Growing Pattern T-Chart
----------------------------------?
of months Number Pattern 2, 4, 6, 8, __,
12, 14. Teepee Rule example(2)
Stem
____
1 Month
2 Months
3 Months
4 Months
5 Months?
of leaves
1 2 3 4 5
1 2 3 4 ?
2

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Money
Hairy Money
1 cent 5 cents 10 cents 25 cents 50 cents
.
Currency the money that is used in a country.
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Telling Time
Analog physical measurement Digital electronic
signal Quarter Before 15 minutes before the
hour Quarter After 15 minutes after the hour

• Look at the hour hand (shortest) and say the
  number. If it is between the numbers you say the
  lowest number or the number before.
• 2. Look at the minute hand (longest), count by
  5s and say the number. If it is on 60, say
  oclock.

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Addition with Regrouping
475 136 _____ 611
The answer to an addition problem is called the
SUM.

1. Put big number on top to help remember for
   subtraction.
2. Make sure the numbers are lined up (ones with
   ones, tens with tens)
3. Look at the ones place if the two numbers equal
   ten or more you will regroup.
4. Bring the ones place down to the ones place and
   carry the ten to the tens place.
5. Look at the tens place and add the regrouped
   number.
6. Add all the numbers in the tens place. If the
   numbers equal ten or more you will regroup.
7. Repeat steps 3 and 5.

Sum, How many are there, Added/Plus, Total, In
all, Altogether, And
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Subtraction with Regrouping
More on top, dont stop! More on the floor, go
next door! Numbers the same, zeros the game!
The answer to a subtraction problem is called the
DIFFERENCE.
How many more/less, How many are left, Spent,
Difference

1. Place the bigger number on top.
2. Make sure numbers are lined up (ones with ones,
   tens with tens, etc.)
3. Start at the ones place and look at the numbers
   to see if you can subtract without regrouping.
4. If the top number is bigger, you can just
   subtract.
5. If the top number is smaller (less than) the
   bottom number, you have to regroup.
6. Take one ten from the tens place and cross it out
   (it becomes one less) (example 3 turns into 2).
7. Add the ten to the ones place.
8. Subtract the ones.
9. Look at the tens repeat steps 3-8.

• 7 3
• 2 9
• ------
• 4 4

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Number Lines

• Look for the RULE!
• Try numbers until you find the rule.

31, 37, ___, 49 (Rule 6)
(Rule -5) 25 ___ 15
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Dont forget your teepees! ()
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2D 3D Shapes
Face Edge Sides Vertices
The corners are called VERTICES.
Rectangular Prism
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Perimeter
90 90 90 90 -------
Outside Add ALL of the sides!
Perimeter the length of the border.
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Area
Area the amount of surface within a certain
space.
Inside Count what you are looking for.
Watch for shaded or NOT shaded!
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Multiplication
Gets bigger!

• Ways to solve
• Loops Groups
• 2. Array
• 3. Repeated addition
• 4. T-Chart
• 5. Algorithm (aka up over)
• (you have to have your facts
• memorized to use this method!)

The answer to a multiplication problem is called
a PRODUCT.
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I I I I
I I I I
I I I I
4 . . . . 3 . . . . . . . .
4 4 4 12
3 X 4 3 4 4 X 3 X 4 X 3 ----- -----
Product, Times, Twice,
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Greater Less Than
Greater Than 36 gt 29
Less Than 15 lt 57
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Fractions
Fraction-an equal part of a whole
number. Numerator-tells us how many parts
UP! Denominator-tells us all the equal parts
DOWN! Equivalent-the same of equal.
3 1 --- are shaded --- is not shaded 4 4
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Rounding Part 1
Round to the nearest About how
many,,, About

• Estimate when you dont need an exact answer.
• Estimate to check your work.

When you see ESTIMATE or ABOUT, round FIRST,
then solve!
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Rounding Part 2
Remember When its in the middle (5), you round
up! 2530
Find the digit, Look next door. Five or
higher, Add one more! Four or less, Let it rest!
Rounds to

• 90
• 40
• ------
• 50

• 93
• 38
• ------

0,1,2,3,4 go to lowest 10 5,6,7,8,9 go up to
highest 10
Rounds to
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Temperature
F C Boiling 212 100 Freezing
32 0
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Fact Families

• Addition/Subtraction fact families are found by
• Starting with a simple fact. ( 2 5 7)
• Changing the numbers around. (5 2 7)
• Writing the Inverse operations for both.
• (7 - 2 5 7 - 5 2)

• Multiplication/Division fact families are found
  by
• Starting with a simple multiplication fact. ( 3
  x 9 27)
• Changing the multiplicands around. (9 x 3 27)
• Writing the Inverse operations for both.
• (27 / 3 9 27 / 9 3)

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Division
Gets smaller!
Look for these words to divide Separate, give,
each, equal
12 / 4 3
I I I I I I I I I I I I
Array
The answer to a division problem is called a
QUOTIENT.
Loops Groups
I I I I I I I I I I I I I I I I
Division Monster
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Separate, Equal, Half, Each (in the question)
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Measurement
12 inches 1 foot your ruler or piece of
paper 3 feet 36 inches 1 yard yard
stick 1 meter light on ceiling 1 mile
5,280 feet school to Wal-Mart 1 inch end
of finger 1 cm 0.01 meter width of pinky
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Congruence
Congruent-same size AND shape.
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Symmetry
Symmetry-one object that when an imaginary line
is drawn through is the same at both ends. Line
of Symmetry-a line that divides a figure/shape
into two mirror images.
Line of Symmetry
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Graphs
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Paired Numbers

• To make two batches of cookies how many eggs do
  you need? For three batches? For four batches?
• How did you find the number of eggs needed to
  make four batches of cookies?

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Probability
More likely than, Less likely than, Equally
likely as
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Range
The range (answer)
12-24
Lowest number
3
Highest number
6
X
X
With range, you will either multiply or divide.
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The number that only has 1 label.