Math for Grownups (34 page)

sales discounts and affordability, 11-15

tax on sales, 3-8

tips for, 15-16

travel costs, 208-14

zeros and, 13

Everyday math.
See also specific topics

common-sense approach to, 211

ease of, vi-vii

problem-solving skills.
See
Equations; Solving problems

Exercise

heart rate calculations, 193-95, 223, 224

high-intensity interval training (HIIT), 195-96

pumping iron, 196-200

weight loss and.
See
Calories; Weight loss

Exponents

calculating, 36, 43, 62, 129

negative, 44-45, 162

order of operations, 35-36

undoing, 175

F

Fabric requirements.
See
Sewing calculations

Factorials, 176

Factors, 151

Fahrenheit/Celsius conversions, 110-12

Fertilizer requirement calculation, 132-33

Finances, 155-79.
See also
Debt; Income; Interest calculations; Retirement

about: overview of, 155

budget considerations, 156-59

net worth, 169-70, 223

taxes, 177-79

Fish pond, stocking calculations, 135-36

Formulas.
See also
specific topics

deriving, 207

glossary of, 221-25

Fractions

adding, 113-14, 115-16, 144

changing denominators, 115-16

common decimal conversions, 147

common denominators, 115-16

converting decimals and percents to/from, 16-17, 147.
See also
Decimals; Percents

cooking with 1/3s and 1/2s, 115-18

dividing, 118-19

improper, 102-3, 117-18, 145

inverting and multiplying, 118-19

least common denominator (LCD), 116

multiplying, 118-19, 141

odds of winning as, 218

ratios as.
See
Ratios

G

Gambling, 214-19

appeal and expectations, 216

house rules and, 219

odds of winning, 216-19

Gardening.
See
Landscaping

Glossary of terms, 227-36

Greater than, 184

Greater than or equal to, 184

Grocery shopping.
See
Estimating; Percents; Shopping

H

Hanging curtains, 93-94

Hanging pictures, 88-92

Heart rate calculations, 193-95, 223, 224

High-intensity interval training (HIIT), 195-96

Houses

annual repair costs, 64

buying.
See
Mortgage(s)

decorating projects.
See
Remodeling and decorating

renting vs. buying, 64

I

Income

calculating, 159-60

debt-to-income ratio, 165-66, 222

negotiating, 159-60

taxes on, 177-79

Interest calculations.
See also
Mortgage(s)

amount-due formula for (A=P(1+r)
ⁿ
, 35-37

compound interest, 163-64

credit card payments, 161-64

monthly payment calculations, 40-46, 161-64, 222

PEMDAS acronym for order of operations, 36

Rule of 72 and, 174-75, 223

simple interest, 164, 223

total cost of car loan, 35-37

Investments

doubling (Rule of 72), 174-75

for retirement.
See
Retirement

K

Kitchen math, 97-119

about: overview of, 97

adding/subtracting time, 108-9

calculating how much to buy, 109

canning jar requirement calculation, 98

conversion chart (teaspoons, tablespoons, cups, pints, quarts, gallons), 101

converting temperatures (Celsius/Fahrenheit), 110-12

cooking with 1/3s and 1/2s, 115-18

improper fractions and, 102-3, 117-18

parts, ratios and, 103-6

refrigerator measurements, 87-88

re-sizing recipes, 99-101, 118-19

substituting ingredients, 112-15

turkey thawing time calculation, 106-8

variables (dependent and independent) and, 110

Knitting and crocheting, 140-42

approach to, 142

changing pattern proportions, 140-41

gauge or tension swatch, 142

L

Landscaping, 121-37

about: overview of, 121

container gardening, 126-29

fertilizer requirement calculation, 132-33

fish pond stocking calculations, 135-36

flowerbed/garden layouts and calculations, 122-26

mulch requirement calculation, 130-32

oddly shaped flowerbeds, 123-25

perimeter calculation, 123, 129

potting soil calculations, 127

weed guard requirement calculation, 122-23

Less than, 184

Less than or equal to, 184

Lottery odds, 175-77

M

Measure, units of, 129, 204-5.
See also
Converting

Memorizing things, 5-6

Metric conversion charts, 147, 204

Monthly lease payment calculation, 47-51, 223

Monthly payment calculations

car payments, 40-46

credit card payments, 161-64

formula, 222

Mortgage(s), 55-75

amount you can afford, 59-60

buying points (or not), 71-72, 73-74

closing costs, 75

confidence to commit to, 55

down payment considerations and calculation, 56-58, 74

equity and, 58-59

fees, 75

fixed vs. adjustable (ARMs),
68-70

interest rates and calculations, 65-70

monthly payment calculations, 60-63

origin of word, 64

PITI (principal, interest, taxes, insurance), 63-65

reducing total of by reducing components (P, r, n), 70-73

total payment formula, 70

Mulch requirement calculation, 130-32

Multiplication

division undoing, 40

doing same thing to both sides of equation, 41

estimating answers.
See
Estimating

of fractions, 40, 141

inverse of, 44.
See also
Division

multiples and, 151

by multiples of 10, 13

order of operations (PEMDAS acronym), 36

of percents, 9

rounding rules, 137

solving for
x
using, 38-40

word clues indicating, 134

Muscle strength, pumping iron and, 196-200

Myths about math, 4-7

memorization is key, 5-6

only one way to solve problems, 4-5

using calculator is cheating, 6-7

N

Net worth, 169-70, 223

Nutrition labels, 191-93

O

Odds

gambling, 216-19

lottery, calculating, 176-77

Order of operations (PEMDAS acronym), 36, 82

P

Paintings, hanging, 88-92

Paint requirements, 78-82

PEMDAS acronym for order of operations, 36, 82

Percents

calculating sales tax and, 3-8

car down payment calculation, 37-40

common daily uses of, 15

converting fractions and decimals to/from, 16-17, 147

as decimals.
See also
Decimals

defined, 16

estimating (3 ways), 12-15

estimating 25%, 9

estimating 50%, 10

finding 5% easily, 3-8

finding 10% easily, 3, 8

finding 15% easily, 9

finding 20% easily, 9

finding
x
in calculations, 38-40

ratios and, 105-6

rounding rules, 137

value of finding quickly, 11

Perimeter calculation, 123, 129

Per-unit cost, 20-21

Photos, proportions of, 152

Pi, 128, 135

Pictures, hanging, 88-92

Pint conversions, 101

Pond, stocking calculations, 135-36

Potting soil calculations, 127

Principal formula, 60-63, 223

Problem-solving.
See
Equations; Solving problems

Proportions.
See also
Fractions; Ratios

changing yarn patterns using, 140-41

defined, 133

of photos, 152

Pumping iron, 196-200

Pyramids, volume of, 225

Q

Quart conversions, 101

R

Radius

area of circles and, 135-36, 221

diameter relative to, 128

surface area of cylinders and, 224

volume of cylinders and, 128-29, 225

Ratios, 103-6.
See also
Fractions

changing, 104, 141-42

debt-to-income, 165-66

defined and explained, 103, 105-6

of fertilizer to water, 133

odds of winning as, 218

parts, kitchen math and, 103-6