Math & Quant Flashcards
Rounding X Truncation
- Rounding: Arredondamento para as casas mais próximas para cima ou para baixo
- Truncation: Apenas desconsidera o resto
1^2
1
2^2
4
3^2
9
4^2
16
5^2
25
6^2
36
7^2
49
8^2
64
10^2
100
9^2
81
11^2
121
12^2
144
13^2
169
14^2
196
15^2
225
16^2
256
17^2
289
18^2
324
19^2
361
20^2
400
2^0
1
2^1
2
2^3
8
2^4
16
2^5
32
2^6
64
2^7
128
2^8
256
2^9
512
2^10
1024
3^3
27
3^4
81
3^5
243
3^6
729
3^7
2187
5^3
125
5^4
625
5^5
3125
6^3
216
7^3
343
7^4
2401
5/4 equals to:
1.25 or 125%
7/4 equals to:
1.75 or 175%
1/8 equals to:
0.125 or 12.5%
3/8 equals to:
0.375 or 37.5%
5/8 equals to:
0.625 or 62.5%
2/5 equals to:
0.4 or 40%
Converting a Fraction to a Decimal
Divide the Numerator by the Denominator.
Ex: 1/4 equals to 1 divided by 4 = 0.25
Converting Fraction to a Percent
Divide the Numerator by the Denominator and move the decimal two places to the Right
Ex: 1/4 equals to 1 divided by 4 = 0.25 then two places to the right = 25%
Converting Decimal to Fraction
Use the place value of the last digit in the decimal as the Denominator and put the decimal’s digits in the numerator and then Simplify
Ex: 0.375 equals to 375/1000 and then simplify to 3/8
Converting Decimal to Percent
Move the decimal point two places to the right
Ex: 0.375 = 37.5%
Converting Percent to Fraction
Use the digits of the percent for the Numerator and 100 for the denominator and then simplify
Ex: 65% equals to 65/100 then 13/20
Prime Number
Números Primos ; Divisíveis por 1 e eles mesmos
Whole Number
Números Inteiros
Digits
They are 10 Symbols (0,1…9)
Inequalities
Expressões que usam o Sinal “<” e “>”
Equations
Expressões que sempre usam o sinal de igual “=”
When to use DISTRIBUTION
When the operations inside the parentheses are “+” or “-“
Perfect Square
É o ao quadrado de um número inteiro.
Ex: 25 é o Perfect Square de 5.
Roots
Roots undo exponents.
The most common is the Square Root.
When the text is talking about a “radical” it’s talking about the Root Symbol
√2
~1.4
√3
~1.7
Coefficient
When we have variables such as “3x” the “3” is the COEFFICIENT of x
PEMDAS
Order which you solve a expression
Parentheses
Exponents
Multiplication / Division
Addition / Subtraction
The use of the word Quantity
Indica que os valores estão dentro de um parênteses
Nome da Primeira Casa Após o Ponto
Casa dos TENTHS –> 0.2
Sinais Iguais dá….
MAIS (+)
+ x + = + ; - x - = +
Opposite Numbers
Números Opostos
Ex: 3 e -3
Reciprocal Numbers
Números Inversos
Ex: 7 e 1/7
Slope
Inclinação da Reta
Rhombus
Losango
NEW YORK Technique
Quando um Statement pode ser YES or NO……ITS NOT SUFFICIENT
Comparing Fractions: The Double-Cross
Set up the fractions next to each other and then multiply the numbers across the arrows.
7/9 and 4/5 –> We would multiply 7x5 and 9x4. Then we would multiply 9 x 5 to get the denominator
Multiple Ratios: Make a Common Term
If we want to find a certain ratio we just need to put all of them in a common term
A : B : C
3 : 2: ?
5: ? : 4
We just need to multiply the know terms and get all of them in the same common term. Here we can use 15 for A. So we are using 5x in the first row and 3x in the second
15: 10 : 12
4 Words of %
Percernt = Divided by 100
OF = Multiply
Is = Equals to (=)
WHAT = unkown value (x)
Percent Change Formula
Percent Change = Change in Value/Original Value
New Percent Formula
New Percent = New Value/Original Value
Division by 3 Rule
if the sum of the digits can be divided by 3 then the number can also be divided by 3
EX: 147 -> 1 + 4 + 7 = 12
Factors
São os números pelos quais um outro determinado número é divisível “evenly”
Factors de 6: 1, 2, 3 e 6
Number is a Divisor of another
On the GMAT when a question states that it means it is an evenly divison
Prime Number
Only divisible by 1 and itself
Prime Factor
É quando nós quebramos um número em sua Prime Factor Tree para chegar aos menores números primos que multiplicados dão aquele número
Ex: 60 -> 4x15 -> 2x2x3x5
Logo, temos que os Prime Factors de 60 são 2,2,3 e 5
NEGATIVE NUMBER POWERED TO AN EVEN NUMBER
Equals to a POSITIVE NUMBER
Ex: -3^2 = 9
NEGATIVE NUMBER POWERED TO AN ODD NUMBER
Equals to a NEGATIVE NUMBER
Ex: -3^3 = -27
DIVIDE TERMS WITH THE SAME BASE: SUBTRACT THE EXPONENTS
If we have an expression which is dividing a two powered numbers by the same base, we can SUBTRACT the exponents
Ex: A^5 / A^3 = A^2
Multiply terms with the same base: add the exponents
If we have an expression which is multiplying a two powered numbers by the same base, we can ADD the exponents
Ex: A^2 x A^3 = A^5
Anything to the power of ZERO
Equals 1
Negative Power
Equals to 1 over a positive number
Ex: a^-2 –> 1/a^2
(a^2)^4
Multiply the exponents
Ex: a^8
If you Square-Root a Square number
You get the original number
The Square-root of a number between 0 and 1 is
Greater than the original number
