4rd grade math

Find here many important 4th grade math concepts taught in 4th grade. Teachers, parents, and math tutors can also use them as a guideline to illustrate a math lesson or to teach important skills that kids are supposed to know in 4th grade math.


Decimal notation for fractions

0.28


Ray
A ray has one endpoint where it starts and it extends forever on the other side.




Add mixed numbers

Add mixed numbers




Comparing fractions


Comparing fractions



Read whole numbers

Which number can be read as six thousand, four hundred eighty-seven?

    A. 64087         B.    6087          

    C. 6487          D.     8764




Read whole numbers

Which number can be read as six thousand, four hundred eighty-seven?

A. 64087     B.    6087          

C. 6487       D.     8764

Proper fraction
Numerator is smaller than denominator
Improper fraction
Numerator is bigger than denominator.


Proper and improper fractions


Right triangle

A right triangle has one right angle.

Right triangle

Benchmark fractions
Fractions that are used frequently to do estimation.

Benchmark fractions

Congruent shapes

Shapes are congruent when they have the same shape and size.

Congruent shapes

Common denominator
Multiples of 3 are
3, 6, 9, 12, 15, ...
Multiples of 4 are 4, 8, 12,16, ...
Common denominator is least common multiple or 12.

Common denominator of 12




Subtraction algorithm
                
      4    5    6
 -    3    9    8
____________

                                       4   16                                  4    5    6
                          -      3    9    8
                          ___________
                                             8

                               3   1 4  16 
                               4     5    6
                            -  3     9    8
                           __________
                               0     5    8




Subtraction algorithm
                
               4    5    6
          -    3    9    8
           ________________

                    4   16            
               4    5    6
     -         3    9    8
          ________________
                           8

             3   1 4  16 
             4    5    6
      -      3    9    8
          ________________
             0    5    8



Line of symmetry

Line of symmetry


Protractor


A geometric tool used
to draw and measure angles

Protractor


Arc

An arc is a part of a circle. The arc is shown in orange.

Arc



Algorithm for multiplication

Algorithm for multiplication


Measure of an angle

The angle on the right measures 150 degrees

150 degrees angles150 degrees


Equation

A mathematical sentence with an equal sign. The equal sign separates the left side from the right side. The amount on the left side of the equation is always equal to the amount on the right side.

                               
                                4  + 6 = 10

                                1 + 12 = 13

                                20 = 9 + 11

Equation

A mathematical sentence with an equal sign. The equal sign separates the left side from the right side. The amount on the left side of the equation is always equal to the amount on the right side.

           4  + 6 = 10

           1 + 12 = 13

           20 = 9 + 11



Tenth  and hundredth

Tenth: one of the equal parts when a whole is divided into 10 equal parts.

Hundredth: one of the equal parts when a whole is divided into 100 equal parts


Tenth and hundredth


Hundredths
The hundredths place is shown in red. The 9 means that 9 parts are colored out of 100.

                     
                     8.29



Intersecting lines

Intersecting lines



Comparing decimals

Put the following decimal in order from greatest to least.
4.23    4.24    4.2    4.30    4.19

Answer :
4.30    4.24   4.23    4.20   4.19

Mixed number
A mixed number has 2 parts. First it has a whole number that is 2. Second, it has a fraction that is 4/5

Example of  a mixed number


Formulas
Area and perimeter of a rectangle

Area  = length x width

Perimeter = 2 x length + 2 x width



Circle
In a circle, you can put points anywhere on the purple arc. These points will be at the same distance from the fixed black point called center.

Example of a circle


Tenths
The tenths place is shown in red. The 2 means that 2 parts are colored out of 10.

                      
                      8.2
9





Composite number
A number with more
than 2 factors. Factors
of 8 are 1, 2, 4, and 8.
8 is a composite number
since it has 4 factors
or 4 numbers than
can divide it evenly

                 
         

         12, 9 and 8          
         
                                      



Factor pairs

A factor pair refers to
a set of two numbers
when multiplied will
yield a specific product.



            Factor pairs of 12
            are  (1,12), (2, 6),
            and (3, 4)

Factor pairs

A factor pair refers to a set of two numbers when multiplied will yield a specific product.


           Factor pairs of 12
           are (1,12), (2, 6),
           and (3, 4)



Obtuse angle

An angle bigger than 90 degrees

Example of an obtuse angle


Decimal

10.50      5.25      61.0     0.40       .333         



Number line
A straight line on which we put 0 and counting numbers

A number line from zero to seven


Reasonableness
There is no need to
do the math. Instead
use estimation to
eliminate answers that
are unreasonable
.
50 times 30 = 1500,
therefore, the answer is 1551


             
       What is the product
            of 47  times  32?
            A. 4514    B. 1551
            C. 2947    D. 8114



Multiplicative comparison

Peter has 5 times 4 = 20. Together they have 20 + 4 = 24


                   John has 4 tennis ball.

                   Peter has 5 times as many
                   tennis ball as John.
                   How many tennis ball do
                   they have together?

Multiplicative comparison

Peter has 5 times 4 = 20.
Together they have
20 + 4 = 24


 John has 4 tennis ball.  
  Peter has 5 times as
  many tennis
ball as John.
  How many tennis ball do
  they
have together?



Perimeter

Perimeter = 2 x length + 2 x width
                  =  2 x 6 + 2 x 2
                  =  12 + 4
                  = 16

Area          =  6 x 2 = 12

Rectangle with a length of six and a width of 2


Solve an equation

  What is the value
  of b in the equation
   below?

   5 + b = 12
   Since 5 + 7 = 12,
    b = 7




1 ounce


  • A slice of bread

  • A CD without the case
  • 2 or 3 strawberries depends on the size

Pattern:
What is the next
number in the list?

   12    15    18



Decompose a fraction

    3/5  = 1/5 + 1/5 + 1/5

Decompose a fraction

    3/5  = 1/5 + 1/5 + 1/5



Example of prime numbers
A prime number is a number
that has only 2 factors, 1
and the number itself.

7 is a prime number because
only 1 and 7 can be
multiplied to get 7


        
           
           5, 7, and 13            

                        



Decimal point

The decimal point is the dot (.) separating the whole number from the fraction in the decimal notation.

Decimal point



Equivalent fractions

Equivalent fractions




Order of operations


                       3 + (2 + 4) x 5
                      Do parenthesis
                       3 + 8 x 5
                      Do multiplication
                       3 + 40
                        Add
                         43


Order of operations

       3 + (2 + 4) x 5
       Do parenthesis
             3 + 8 x 5
       Do multiplication
              3 + 40
        Add
         43


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