## Thursday, June 14, 2012

### Circle Graphs

-Sectors of circle graphs are made from central angles

-If the sector covers 25% of the graph, the central angle is 25% of 360 (degrees) . Which is 90 (degrees).

### Circle Formulas

c = (pi) d

c = 2 (pi) r

d = 2r

A = (pi) r2

Area is the measure of space a 2D shape covers.

### Divisibility Rules

0 = ends in zero
1 = all numbers
2 = even numbers
3 = sum of the digits is 3
4 = divisible by 2 twice
5 = ends in a 0 or 5
6 = divisible by 2 and 3
8 = divisible by 2 thrice
9 = sum of the digits is 9
10 = ends in 0

### Integers

Integers

Negative numbers represent values below
zero and positive numbers represent
values above zero

eg. above and below ground or sea level

1+ (-2) = (-1) is an addition statement

3 - (-1) = 4 is an subtraction statement

### Intergers

Opposite integers have the same numeral
but different sing eg. 3 and (-3)

know what a (+) + (+) =       (+) - (+) =
(-) + (-) =        (-) - (-) =
(+) + (-) =       (+) - (-) =
(-) + (+) =       (-) - (+) =

### Divisibility

Definition:

Divisible-  Means when a number can be divided by another number, with no remainder or decimal.

(It's a whole number.)

### Probability

DEFINITIONS

Experimental probability:  Actually doing the trails

Theoretical probability:  what you expect to happen