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

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

         ♥ ♥        ♥ ♥
♥ ♥ ♥ ♥   ♥ ♥ ♥  ♥ ♥ ♥ ♥ ♥     ♥ ♥ ♥ ♥ ♥ ♥       ♥ ♥ ♥ ♥ ♥ ♥ ♥ ♥ ♥ ♥ ♥

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

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.

1 Dollar

1 dollar  = 100 cents

Number line

Word form of number

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

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.

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.

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

Place value

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