Second grade math

Find here many important second grade math concepts taught in second 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 second grade math.

Doubles

In doubles, both addends are the same.

1 + 1 = 2                2 + 2 = 4
3 + 3 = 6                4 + 4 = 8
5 + 5 = 10             6 + 6 = 12

How to decompose a number

Equal groups
Groups have the same number of items.

Estimate:
No need to get an exact answer.
Possible answer: 35, 40 or 30

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What is the meaning of a.m. ?

12:00 a.m. : midnight;sleeping time
7:30 a.m. : half past 7; wake up time
10:15 a.m.: a quarter after 10; doing work in class.

Example of angle.
When two lines meet at a common point, they make an angle.

Bar graph
A graph that uses rectangles to compare data. Saturday got 15 votes

Array
The array on the right is made with triangles. The array has 4 rows and 5 columns.  4 × 5 = 20 triangles

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What is the associative property ?

8 + 5 + 2     =    (8 + 5)  + 2
                   =    8 + (5 + 2)         

Even number
There are 10 balls and 10 is an even number. An even number has 2 equal parts. 10 has 2 equal parts. Each part is equal to 5.

Count back

7 - 4

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1 Dollar

1 dollar  = 100 cents

What is a number line ?

Word form of number

345: three hundred, forty-five
268: two hundred sixty-eight

More interesting and important second grade math concepts.

Odd number
There are 9 balls and 9 is an odd number. An odd number does not have 2 equal parts. One part is is 5 and the other is 4. 

Quadrilaterals
Quadrilaterals are closed figures with 4 straight sides.

Standard form

A familiar way of writing numbers using digits

432

Tens
1 long is a physical representation of 10

Vertex
A point where 2 or more sides of shape meet. The vertex is the cube on the right is shown with a small white circle. The vertex of the triangle is shown with a small red circle.

Fourths
The parts that we get when something is divided into 4 equal parts.

What is the meaning of p.m. ?

12:00 p.m. : noon ; lunch time
3:30 p.m. : half past 3 ; nap time
6:45 p.m.: a quarter to 7 ; dinner time

Line plot
A line plot shows data on a number line using x or some other marks to show how many times a number appears. The number 6 appears 3 times.

What is an equation?

 4 + 8  = 12
   
14  =   6 + 8

Compare numbers

4 is smaller than 8 or 4 < 8

8 is bigger than 4 or 8 > 4

Centimeter ruler

Centimeter or cm
1 meter = 100 centimeters
The length of a baseball bat is about 1 meter
The width of a finger or the diamater of a wedding ring is about 1 centimeter long

Count on
5 + 3

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USA money
One dollar + 1 quarter + 1 dime + 1 nickel + 1 penny = 1 dollars and 41 cents.

Fractions

Regroup
Regroup 15 ones as 1 ten and 5 ones

Pictograph
Key of a pictograph. Each face = 1 player.
2 people loves soccer.

Flat
10 tens or 10 long  = 1 hundred or 1 flat

Sequence

      +5      +5           +5
3         8      13     18

Place value
The value of a digit based on where the digit is located. The place value of 4 in 546 is 40.