Idiot\'s Guides Basic Math and Pre-Algebra

354 Idiot’s Guides: Basic Math and Pre-Algebra

octagons, 192

one-step equations, 123-124

order of operations, 32

distributive property, 36-38

example problems, 33-35

PEMDAS memory device, 33

origins, coordinate graphing, 134

“or” probabilities, 257-258

P

parallel lines, 159-160

angle formations

alternate exterior, 161

alternate interior, 161

corresponding angles, 160

slopes, 162-163

transversals, 160

parallelograms, 181-183

rectangles, 184

rhombus, 185-186

squares, 185-186

PEMDAS (Parentheses,

Exponents, Multiply, Divide,

Add, Subtract), 114

pentagons, 192

percentages, 88

changing to decimals, 92

changing to fractions, 92

example problems, 90-91

increases and decreases, 96-98

interest calculations, 92-94

APR (annual percentage

rate), 93

I = Prt formula, 93-94

principals, 93

tax calculations, 94-95

tip calculations, 95-96

percentiles, dividing data sets,

281-282

numbers

composite numbers, 46-47

counting, 4

decimal system, 5-9, 68-79

GCF (greatest common

factor), 52-54

integers

absolute values, 39

adding signed numbers,

40-41

dividing signed numbers,

43- 4 4

multiplying signed

numbers, 42-43

number lines, 38-39

subtracting signed numbers,

41- 42

irrational, 80-81

LCM (least common multiple),

54-55

natural, 4

place values, 5

prime numbers, 46

divisibility test, 48

finding, 47-49

relatively prime, 53

square numbers, 49-50

rational numbers, fractions,

58-66

real, 80

reciprocals, 62

Roman numerals, 4-5

rounding, 11-12

scientific notation, 9-10

whole numbers, 4

numerators (fractions), 58

O

obtuse angles, 156

obtuse triangles, 172

medians, 277-279
trapezoids, 187
triangles, 167
midpoints, 158
segment bisectors, 158-159
minor arcs, 198-199
minuends, 21
mixed number fractions, 59
modes, 279-280
monomials, 117
multiples, LCM (least common
multiple), 54-55
multiplication
basic facts, 23-26
cross-multiplication
(proportions), 87-88
decimal fractions, 75-78
factors, 23
fractions, 61-64
lattice multiplication, 27
prime factorization
factor trees, 50-51
using exponents, 52
products, 23
reciprocals, 62
signed numbers, 42-43
variables
exponents, 104 -105
rules, 105

N

naming polygons, 192
natural numbers, 4
negative numbers
addition, 40-41
division, 43-44
multiplication, 42-43
subtraction, 41- 42
nonagon, 192
number lines (integers), 38-39