math circle

If you think that this site is helpful, please recommend your friends to visit our site.

Area of the circle

The area of a circle is p ?r2 or p ?r ?r, where r is the length 
of its radius. p is a number that is approximately 3.14159. 

Example: 

What is the area of a circle having a radius of 4.2 cm, to the 
nearest tenth of a square cm? Using an approximation of 3.14159 for 
p, and the fact that the area of a circle is p ?r2, the area 
of this circle is p ?4.22, that is, 3.14159 ?4.22 =55.41 
square cm, which is 55.4 square cm when rounded to the nearest 
tenth. 


Perimeter of the circle

The perimeter of a circle is called the circumference, and is found 
by multiplying the radius of the circle by 2p. p is a special 
irrational number that was discovered by the Greeks centuries ago. 
It is always involved in finding measurements of circles, cones and 
spheres. 

Formula:  pr2

Number Elements Write Number Number Greatest Least Number Greater Less Number Pattern Number Comparison Number Fill Blanks Before/After Number Fill Blanks - Middle Tell Numbers Find Numbers Ordering Number Math Number Position Number Counting Number Word Number Word Number Number Even Odd Number CatchIt game

Addition

addition Addition Blank puzzle Addition Brick game Math Addition Concentration game Math Addition Match game Math Addition Shooting game Math addition Match game 1+1 Math addition Match game 2+1 Math addition Match game 2+2 Addition CatchIt game Addition Puzzle

Subtraction

subtraction Subtraction fill Blank puzzle Subtraction Brick game Subtraction Concentration game Subtraction Match game Subtraction Shooting game Subtraction Match game 2-1 subtraction CatchIt game subtraction Puzzle

Multiplication

multiplication multiplication fill Blank puzzle multiplication Brick game multiplication Concentration game multiplication Match game multiplication Shooting game multiplication Match game 1x1 multiplication Match game 2x1 Multiplication CatchIt game Corresponding multiplication Expression Multiplication Biggest Number Multiplication Puzzle

Division

division division file Blank puzzle division Brick game division Concentration game division Match game division Shooting game division Match game 2/1 Division CatchIt game Division Biggest Number Division Puzzle

Mixed Operation

Magic Square Arithmetic Puzzle Arithmetic Operator Mixed Operation Graph Sum Difference Puzzle Math Mixed Operation-Cross Puzzle Math Triangle Puzzle

Fraction

Basic Fraction Fraction Reduction Equivalent Fraction Fraction Whole Number Fraction Comparison Fraction Match Find Same Denominator Decimal Fraction Addition Fraction Subtraction Fraction Multiplication Fraction Division Fraction

Decimal

Decimal Addition Decimal Subtraction Decimal Multiplication Decimal Division Decimal Comparison Decimal Place Value Decimal Find Place Value Decimal Percent Decimal Fraction Addition Decimal Subtraction Decimal Multiplication Decimal Division Decimal

Negative Number

Addition Negative number Subtraction Negative number Multiplication Negative number Division Negative number Negative number CatchIt game

Percent

Find Percentage Percentage Conversion Percentage Find Percent Fraction Decimal Percent Percent Decimal Percent Puzzle Decimal Percent

coordinate

Find Coordinate Math Coordinate Shooting game

Time

Tell Time

Equations

Equation Basics Equations Addition Equations Subtraction Equations Multiplication Equations Division Equations Question Equations Inequality Equations Puzzle

Geometry

geometry Geometry Angle Geometry Area Geometry Perimeter

Word Problems

Math Word Problems

Tools

Square Root Calculator Fraction Calculator Fraction Reducer Prime Number Checker Circle Calculator Percentage Calculator Power Calculator Addition worksheet / test Generator Subtraction worksheet / test Generator Multiplication worksheet / test Generator Division worksheet / test Generator

Others

Factor Tree formula Power Calculation Scientific Notation