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Praxis Math
Question | Answer |
---|---|
Number divisible by 2 if | it's even |
Number divisible by five if | the last digit is a five or 0 |
Number is divisible by 3 if | the Sum of its digits is divisble by 3 |
Number is divisible by nine if | the sum of its digits is divisible by nine |
Number is divislbe by 4 if | the last 2 digits are divisible by 4 |
Factors are | A list of all the ways we can multiply to get a number Ex: for 4, its 1, 2 and 4 |
Prime numbers are | Numbers that their only factors are 1 and itself Ex: 13, |
composite numbers are | Opposite of prime Numbers that have factors other than one and itself |
Prime factorization | Breaking up the factorization into usingo nly primes Ex: 18 = 3 x six break it up into 3 x 2 x 2 |
To find the common factor of 2 numbers | List out the factors of each number and circle the numbers they have in common |
To find the greatest common factors | Find the common factor, and circle the highest number the two have in common |
Rational numbers | are any numbers that can be written as a fraction Ex: 7 because it can be written as 7/1 .33333 repeating because it can be written as 1/3 1.five because it can be written as 3/2 |
Irrational numbers | numbers that cannot be written as fractions ex: Pi, anything with repeating decimals and most square roots and cubes |
Commutative property | states that we can swap numbers and still arrive at the same answer Ex: 2 + 3 = 3 + 2 3 x 2 = 2 x 3 |
Associative property | it doesnt matter which numbers we add/multiply first 8 x 4 x 2 = 4 x 2 x 8 4 + 2 + 1 = 1 + 4 + 2 |
order of operations | 1. do things in parentheses first 2. exponents xpowers, roots) before multiply, divide add or subtract 3. multiply or divide before add/subtract *otherwise go left to right |
remember order of operations | PEMdAS *P parenthese first *E exponents, power roots etc. *Md multiplication and division, left to right *AS addition and subtraction left to right After you have done P, E do md L to R as you find them After PEMd, do A S from L to R as you find |
remebering place value | King Henry doesnt Usually drink chocolate milk Kilo*1000 Hecto*100 dea*10 deci*.10 centi*.01 milli*.001 |
add 2 fractions with diff denominators | find common denominator and add numerators acorss |
subtract two fractions with diff denominators | find common denominator and subtract across |
add and subtract decimals | line them up according to the decimal place, add zeros for them to match up |
multiply two fractions with diff denominators | multiply the numerator and denominator across, do not need a common denominator |
divide two fractions | ddoes not matter if they have a common denominator, flip the second one and multiply across |
addition of two numbers with the same sign | they keep their sign |
addition of two different numbers, one positive one negative | subtract the lesser absolute value from the greater aboslute value, takes the sign of the number with the greatest absolute value |
multiply or divide two signed numbers | both the same, keep positive both different, keep negative |
addition keywords | find a sum, total, combine quantities, increase a quantity |
subtraction keywords | find a difference, take away, find out how much is left, how many more/less, decrease |
multiplication keywords | find a product, put equal quantities together to find a total, how much is a portion of a whole, cost of a given number, percent |
division keywords | find a quotient, ratio/fractional part, how many equal parts in a whole, seperate into groups, probability |
1 pint | 2 cups |
1 quart | 2 pints |
1 gallon | 4 quarts |
1 lb | sixteen ounces |
1 ton | 2000 lbs |
1 meter | 100 centimeters, 1000 mm |
i kilometer | 1000 meters |
1 gram | 1000 milligrams |
1 kilogram | 1000 grams |
perimeter | area around the outside of a figure |
area | space inside the figure |
surface area | area of all the sides of the 3 dimensional figure |
volume | amount of space inside a solid |
Area of triangle | a = 1/2bh |
area of rectangle | a = lw |
area of trapezoid | a = 1/2hXb1 + b2) |
parallelogram | A = bh |
area of circle | A = pie times radius squared |
surface area of a prism/pyramid | sum of all areas of all faces of the figure |
surface area of a cylinder | sum of the areas of the two bases and the area of it's rectangular wrap SA = 2 times pie radius squared + 2 times pie radius times height |
surface area of a sphere | SA = 4 pie radius squared |
volume of a prism/cylinder | V = bh |
volume of pyramid | V = 1/3bh |
volume of a sphere | v = 4/3pie radius squared |
what is congruency | means that figures can fit exactly on top of each other, same size, shape, etc. hash marks can be used to denote this. |
complementary angles | 2 angles whose sum equals 90 degress example: one 30 degree one 60 degree angle |
supplementary angles | two angles whose sum equals 180 ex 1 135 degree angle, 1 45 degree angle |
polygon | shape consisting of straight lines, the name of the shape depends on the number of sides the shape has |
sum of interior angles of a polygon | (n-2)180 n represents the number of sides the polygon has for triangle it would be 3-2, etc |
equilateral triangle | has three congruent sides |
isoceles triangle | has two congruent sides |
scalene triangle | has no congruent sides |
acute triangle | has three acute angles |
obtuse triangle | has one obtuse angle |
right triangle | has one right angle |
difference between rhombus and parallelogram | rhombus has four congruent sides |
sum of interior angles of 1. triangle 2. quadrilateral | 1. 180 2. 360 |