Pre-Algebra / Misc Math / Statistics

Question 1

DDX

Answer 1

Denominator X Denominator, Cross Multiply

operations on dissimilar fractions (+/-)

Question 2

of

changing questions to equations

Answer 2

x

multiply

Question 3

is

changing questions to equations

Answer 3

=

Question 4

what

changing questions to equations

Answer 4

N

unknown

Question 5

arithmetic sequence formula

to get nth term of sequence

Answer 5

an = a1 + (n-1)d

a1 = first term
n = number of terms
d = common difference

Question 6

arithmetic sequence shortcut

number of terms

Answer 6

(last term - first term) / common difference
+ 1

Question 7

arithmetic sequence shortcut

average of all terms

Answer 7

(last term + first term) / 2

Question 8

arithmetic sequence shortcut

sum of all terms

Answer 8

(last term + first term) / 2
x number of terms

average x number of terms

Question 9

calculating page numbers

inclusive of pages

Answer 9

last page - first page + 1

Question 10

calculating page numbers

exclusive of pages

Answer 10

last page - first page - 1

Question 11

how to get root of decimal

Answer 11

• drop decimal points
• perform root operation
• divide decimal places of orig by index of root to get dp of final answer
• move decimal point accordingly

Question 12

DOST

Answer 12

Distance Over Speed / Time

used for distance problems

Question 13

Percent Something

Answer 13

something / original
x 100

used to get the percent of a number from the original

same as PERCENT INCREASE
- increase / orig x 100

Question 14

JUTSU

Jepjep’s Ultimate Technique, Super Ultimate

Answer 14

1. repeating or non-repeating
2. order important or not

used in permutation and combination questions

order important: SAD (sequences/seats, arrangements, digits)
order Not important: GC (group, choose/select)

Question 15

JUTSU

combination formula

Jepjep’s Ultimate Technique, Super Ultimate

Answer 15

answer in R/NR /
blank!

blank! = number of blanks factorial

Question 16

trends on fractions

same denominator

Answer 16

higher numerator
higher fraction value

directly proportional

Question 17

trends on fractions

same numerator

Answer 17

higher denominator
lower fraction value

indirectly proportional

Question 18

Compound Interest Formula

Answer 18

A(t) = P(1+r/n)^nt

P : principal
r : rate of interest (convert % to decimal)
n : compounding process (annual, monthly, etc.)
t : time

Question 19

UTOT Techinque

Simple Interest Formula

Answer 19

I = Prt

P : principal
r : rate of interest (convert % to decimal)
t : time

Question 20

A ∪ B

a union b

Sets Theory

Answer 20

A+B - A∩B

union : or
ornion

Question 21

A ∩ B

a intersection b

Sets Theory

Answer 21

A+B - A∪B

intersection: and
andtersection

Question 22

Golden Average Rule

don’t average the average

Answer 22

final ave = total sum / total n

total sum = average x n

Question 23

Average Speed

don’t average the average
speed is average

Answer 23

ave. speed = total distance / total time

Question 24

pigeonhole principle

Answer 24

worst case scenario + 1

can be used in minimum number of students or minimum number of draws

Question 25

geometric sequence

Answer 25

sequence with common ratio

a number is multiplied or divided to each term to get the next one

Question 26

percentile, docile, and quartile formula

percentile : divides data set into 100 parts
docile : divides data set into 10 parts
quartile : divides data set into 4 parts

Answer 26

L = j/k
x N

L : observation at certain location
j : location under percentil/docile/quartile
k : division of data set
N : population or sample size

Question 27

mean

measure of central tendency

Answer 27

average

Question 28

median

measure of central tendency

Answer 28

middle value when data set is arranged from lowest to highest

Question 29

mode

measure of central tendency

Answer 29

most common value

number that appeared the most times

Question 30

probability formula

Answer 30

P = number of desired / total outcomes