Selcat

Please (Parentesis)

Excuse (Exponents)

My (Multiply)

Dear (Divide)

Aunt (Add)

Sally (Subtract)

MD & AS from left to right!

To get the reciprocal of a number, we divide 1 by the number.

The reciprocal is also called the "Multiplicative Inverse"

Example: the reciprocal of 2 is ½ (a half)

The reciprocal of 4 is ¹/₄

The reciprocal of ¹/₄ is 4 (back to 4 again)

Example: the reciprocal of ³/₄ is ⁴/₃

Every number has a reciprocal except 0

2 × (¹/₂) =

10 × (¹/₁₀) =

You should always use metric units in your work

T (tera-trillion) 1,000,000,000,000

G (giga-billion) 1,000,000,000

M (mega-million) 1,000,000

k (kilo-thousand) 1,000

h (hecto-hundred) 100

da (deka-ten) 10

unit1  

unit 1

d (deci-tenth) 0.1

c (centi-hundredth) 0.01

m (milli-thousandth) 0.001 µ

(micro-millionth) 0.000 001

n (nano-billionth) 0.000 000 001

p (pico-trillionth) 0.000 000 000 001

1 inch [in] = 2.54 cm

1 foot [ft] = 12 in = 0.3048 m

1 yard [yd] = 3 ft = 0.9144 m

1 mile = 1760 yd = 1.6093 km

If you know 1in = 2.54cm, you can find the rest

The exponent of a number says how many times to use the number in a multiplication.

8² could be called "8 to the power 2" or "8 to the second power", or simply "8 squared"

In 8² the "2" says to use 8 twice in a multiplication,

so 8² = 8 × 8 = 64

2^4 is the same as 2⁴

 how many times do we end up multiplying "x"? Answer: "m" times, then reduce that by "n" times (because we are dividing), for a total of "m-n" times.

Example: x⁴/x² = (xxxx) / (xx) = xx = x²

So, x⁴/x² = x^(4-2) = x²

So (x³)⁴ = x^3×4 = x¹²

Example: (x/y)³ =x³/y³

To evaluate an 3xpression is to:

Replace (substitute) its variable with a given number or expression.

evaluate   2x+4 for x=5

Just replace the variable "x" with "5":

2×5 + 4 = 14

There is no "one perfect way" to solve all equations.

our goal is to end up with x = something

we want to move everything except "x" (or whatever name the variable has) over so that it is alone on one side of the equal sign.

Start with: 3x−6 = 9

Add 6 to both sides: 3x = 9+6

Divide by 3: x = (9+6)/3

Now we have x = something,

and a short calculation reveals that x = 5