Circle formulas

C= 3.14 x diameter
C= 2(3.14) r
D= 2(r)
A= 3.14 (r)2

BEDMAS review

Brackets
Exponents
Division
Multiplication
Addition
Subtraction

Definitions for Mean, Median, Mode and Range

Mean- add up all the values then divide by how many values there are

Median- The middle number in a set of ordered values, might be the mean of 2 values

Mode- in the value that shows up the most

Range- positive difference between largest and smallest values

Decimals, Fractions and Percents

50% = 0.5 = 1/2
0.5 x 100= 50 or 50 %
1 divided by 2 = 0.5


How to get from fraction, to percent, to decimal

1/4= 0.25 x 100= 25 or 25%
1 divided by 4= 0.25 times 100 = 25 or 25 percent

Divisibility rules review

1- all numbers
2- all even numbers
3-sum of the digits are divisible by 3
4-divisible by 2 twice
5- ends in 0 or 5
6- number must be divisible by 2 and 3
8- divisible by 2 three times
9- sum of the digits is divisible by 9
10- ends in 0

How to add fractions with the same denominator

When you add fractions with common denominators, all you have to add is the numerator and when you get the sum of adding the 2 numerators you put the sum as the numerator and the denominator you had as a common denominator the denominator.

Here is an example of adding fractions with common denominators.

Definitions we need to study

These are the new definitions that will help us during this new part in math

Variable- letter that represents an unknown number

example- x,a,n


expression- any single number or variable, or combination of operations involving numbers and variables

ex- 5,n,8+,x+1,2y-7


value- a known or calculated ammount


constant number- a number that does not change and it increase or decrease the value of an expression.


numerical coefficient- a number that multiplies the variable

example- 2t