This is a draft cheat sheet. It is a work in progress and is not finished yet.
Interest Formula
Simple Interest |
Prt |
Annual Compound Interest |
P(1r)t |
Compound Interest (x/year) |
P(1r/x)xt |
Combinatorics
|
n!/((n-k)k!)! |
|
n!/(n-k)! |
Circular |
(n-1)! |
Geomtery
30-60-90 |
Sides: 1:2:√3 |
Surface Area: Cyclinder |
2πr22πrh |
cos60 |
1/2 |
Slope |
(y2-y1)/(x2-x1) |
Quadratic Equations
ax2 + bx + c=0 |
x = (b±√(b24ac))/2a |
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|
Number Divisibility
2 |
Last digit is 0, 2, 4, 6 or 8 |
3 |
Sum of digits divisible by 3 |
4 |
Number formed by the last two digits is divisible by 4 |
5 |
Last digit is either 0 or 5 |
6 |
Divisible by 2 AND 3 |
8 |
Number formed by the last three digits is divisible by 8 |
9 |
Sum of the digits is divisible by 9 |
Combined Rate
Total Rate |
Rate X Rate Y |
Total Time |
AB/(A+B) (A & B are times for individual) |
|
|
Number Properties
ODDODD |
ODD |
EVENEVEN |
EVEN |
EVENODD |
EVEN |
ODD ± EVEN |
ODD |
ODD ± ODD |
EVEN |
EVEN ± EVEN |
EVEN |
Avg. of EVEN Number Of consecutive integers |
Not an INTEGER |
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