secrets-of-mental-math-malestrom

More documents

Recommendations

Info

218 Secrets of Mental Math Year Code Year Code Year Code Year Code 2000 0 2025 3 2050 6 2075 2 2001 1 2026 4 2051 0 2076 4 2002 2 2027 5 2052 2 2077 5 2003 3 2028 0 2053 3 2078 6 2004 5 2029 1 2054 4 2079 0 2005 6 2030 2 2055 5 2080 2 2006 0 2031 3 2056 0 2081 3 2007 1 2032 5 2057 1 2082 4 2008 3 2033 6 2058 2 2083 5 2009 4 2034 0 2059 3 2084 0 2010 5 2035 1 2060 5 2085 1 2011 6 2036 3 2061 6 2086 2 2012 1 2037 4 2062 0 2087 3 2013 2 2038 5 2063 1 2088 5 2014 3 2039 6 2064 3 2089 6 2015 4 2040 1 2065 4 2090 0 2016 6 2041 2 2066 5 2091 1 2017 0 2042 3 2067 6 2092 3 2018 1 2043 4 2068 1 2093 4 2019 2 2044 6 2069 2 2094 5 2020 4 2045 0 2070 3 2095 6 2021 5 2046 1 2071 4 2096 1 2022 6 2047 2 2072 6 2097 2 2023 0 2048 4 2073 0 2098 3 2024 2 2049 5 2074 1 2099 4 Hence March 19, 2061, has Month Code Date Year Code 2 19 6 27
Presto-digit-ation: The Art of Mathematical Magic 219 Subtracting 27 21 6 tells us that this date will take place on Saturday. What about birth dates between 1900 and 1999? Do the problem exactly as in the previous calculation, but shift the final answer forward by one day (or simply add 1 to the year code). Thus March 19, 1961, occurred on a Sunday. For the date December 3, 1998, we have 9 8 4 24 (with a remainder of 2 that we ignore). Thus 1998 has year code 98 24 1 123, where the plus one is added for dates in the 1900s. Next, subtract the biggest multiple of 7. For handy reference, here are the multiples of 7 that you might need: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98, 105, 112, 119, 126, ... Since 123 119 4, 1998 has a year code of 4. Therefore, December 3, 1998, has Month Code Date Year Code 4 3 4 11 and 11 7 4, so this date occurred on a Thursday. For dates in the 1800s, we add 3 to the year code. For example, Charles Darwin and Abraham Lincoln were both born on February 12, 1809. Since 2009 has a year code of 4, then 1809 has a year code of 4 3 7, which can be reduced to 0. Thus, February 12, 1809, has Month Code Date Year Code 2 12 0 14 and 14 14 0, so they were both born on a Sunday.
Page 2 and 3:
This book has been optimized for vi
Page 5 and 6:
SECRE+S OF MEN+AL MA+H The Mathemag
Page 7:
I dedicate this book to my wife, De
Page 11 and 12:
Contents Foreword by Bill Nye (the
Page 13 and 14:
Foreword by Bill Nye (the Science G
Page 15 and 16:
Foreword xiii Well, actually, I hop
Page 17:
Foreword xv there are also an infin
Page 20 and 21:
xviii Foreword math nut. Immunizati
Page 22 and 23:
xx Prologue in on his secrets of
Page 24 and 25:
xxii Prologue where he learned thes
Page 26 and 27:
xxiv Introduction Too often, math i
Page 28 and 29:
2 Secrets of Mental Math 35 2 What
Page 30 and 31:
4 Secrets of Mental Math Absolutely
Page 32 and 33:
6 Secrets of Mental Math Similarly,
Page 34 and 35:
8 Secrets of Mental Math Although I
Page 36 and 37:
10 Secrets of Mental Math Exception
Page 38 and 39:
12 Secrets of Mental Math math in y
Page 40 and 41:
14 Secrets of Mental Math 67 28 8
Page 42 and 43:
16 Secrets of Mental Math 858 7 re
Page 44 and 45:
18 Secrets of Mental Math lot easie
Page 46 and 47:
20 Secrets of Mental Math Carl Frie
Page 48 and 49:
22 Secrets of Mental Math Of course
Page 50 and 51:
24 Secrets of Mental Math 958 417
Page 52 and 53:
26 Secrets of Mental Math to 10. We
Page 54 and 55:
28 Secrets of Mental Math By roundi
Page 56 and 57:
30 Secrets of Mental Math mentally,
Page 58 and 59:
32 Secrets of Mental Math 48 40 8
Page 60 and 61:
34 Secrets of Mental Math problems
Page 62 and 63:
36 Secrets of Mental Math 3-BY-1 MU
Page 64 and 65:
38 Secrets of Mental Math sometimes
Page 66 and 67:
40 Secrets of Mental Math 376 (300
Page 68 and 69:
42 Secrets of Mental Math 925 (900
Page 70 and 71:
44 Secrets of Mental Math BE THERE
Page 72 and 73:
46 Secrets of Mental Math 41 2 1 42
Page 74 and 75:
48 Secrets of Mental Math other squ
Page 76 and 77:
50 Secrets of Mental Math WHY THESE
Page 78 and 79:
52 Secrets of Mental Math Similarly
Page 80 and 81:
54 Secrets of Mental Math Gardner o
Page 82 and 83:
56 Secrets of Mental Math same digi
Page 84 and 85:
New and Improved Products: Intermed
Page 86 and 87:
60 Secrets of Mental Math 59 (60 1
Page 88 and 89:
62 Secrets of Mental Math 88 (90 2
Page 90 and 91:
64 Secrets of Mental Math To see ho
Page 92 and 93:
66 Secrets of Mental Math Remember
Page 94 and 95:
68 Secrets of Mental Math 67: 67 3
Page 96 and 97:
70 Secrets of Mental Math EXERCISE:
Page 98 and 99:
72 Secrets of Mental Math Rounding
Page 100 and 101:
74 Secrets of Mental Math 2. The ea
Page 102 and 103:
76 Secrets of Mental Math 13 1,000
Page 104 and 105:
78 Secrets of Mental Math Chapter 8
Page 106 and 107:
Chapter 4 Divide and Conquer: Menta
Page 108 and 109:
82 Secrets of Mental Math Let’s t
Page 110 and 111:
Page 112 and 113:
86 Secrets of Mental Math In using
Page 114 and 115:
88 Secrets of Mental Math 682 23 I
Page 116 and 117:
Page 118 and 119:
92 Secrets of Mental Math original
Page 120 and 121:
94 Secrets of Mental Math way is to
Page 122 and 123:
96 Secrets of Mental Math 6 7 8 .
Page 124 and 125:
98 Secrets of Mental Math You can e
Page 126 and 127:
100 Secrets of Mental Math A number
Page 128 and 129:
102 Secrets of Mental Math Divisibi
Page 130 and 131:
104 Secrets of Mental Math It is al
Page 132 and 133:
106 Secrets of Mental Math So, To a
Page 134 and 135:
Chapter 5 Good Enough: The Art of
Page 136 and 137:
110 Secrets of Mental Math Notice t
Page 138 and 139:
112 Secrets of Mental Math 8,367 5
Page 140 and 141:
114 Secrets of Mental Math onds doe
Page 142 and 143:
116 Secrets of Mental Math We obser
Page 144 and 145:
118 Secrets of Mental Math Divide:
Page 146 and 147:
120 Secrets of Mental Math roots. I
Page 148 and 149:
122 Secrets of Mental Math MORE TIP
Page 150 and 151:
124 Secrets of Mental Math I will s
Page 152 and 153:
126 Secrets of Mental Math number o
Page 154 and 155:
128 Secrets of Mental Math and sinc
Page 156 and 157:
130 Secrets of Mental Math EXERCISE
Page 158 and 159:
132 Secrets of Mental Math COLUMNS
Page 160 and 161:
134 Secrets of Mental Math As illus
Page 162 and 163:
136 Secrets of Mental Math 4. 3 5 8
Page 164 and 165:
138 Secrets of Mental Math Next, we
Page 166 and 167:
140 Secrets of Mental Math You have
Page 168 and 169:
Page 170 and 171:
144 Secrets of Mental Math Step 4.
Page 172 and 173:
146 Secrets of Mental Math Shakunta
Page 174 and 175:
148 Secrets of Mental Math Here’s
Page 176 and 177:
150 Secrets of Mental Math EXERCISE
Page 178 and 179:
152 Secrets of Mental Math work by
Page 180 and 181:
154 Secrets of Mental Math words: m
Page 182 and 183:
156 Secrets of Mental Math 93: bum,
Page 184 and 185:
158 Secrets of Mental Math And: 69
Page 186 and 187:
Page 188 and 189:
162 Secrets of Mental Math 362 beco
Page 190 and 191:
164 Secrets of Mental Math learned
Page 192 and 193:
166 Secrets of Mental Math Once you
Page 194 and 195: 168 Secrets of Mental Math Thomas F
Page 196 and 197: 170 Secrets of Mental Math numbers
Page 198 and 199: 172 Secrets of Mental Math Then do
Page 200 and 201: 174 Secrets of Mental Math 629 (630
Page 202 and 203: 176 Secrets of Mental Math 858 15
Page 204 and 205: 178 Secrets of Mental Math Using th
Page 206 and 207: 180 Secrets of Mental Math Adding 8
Page 208 and 209: 182 Secrets of Mental Math If both
Page 210 and 211: 184 Secrets of Mental Math I diagra
Page 212 and 213: 186 Secrets of Mental Math In our n
Page 214 and 215: 188 Secrets of Mental Math produces
Page 216 and 217: 190 Secrets of Mental Math be conve
Page 218 and 219: 192 Secrets of Mental Math (e.g., 4
Page 220 and 221: 194 Secrets of Mental Math As with
Page 222 and 223: 196 Secrets of Mental Math I should
Page 224 and 225: 198 Secrets of Mental Math Since yo
Page 226 and 227: 200 Secrets of Mental Math 3. divid
Page 228 and 229: 202 Secrets of Mental Math Hence, a
Page 230 and 231: 204 Secrets of Mental Math 2 on lin
Page 232 and 233: 206 Secrets of Mental Math 1 5 2
Page 234 and 235: 208 Secrets of Mental Math The quot
Page 236 and 237: 210 Secrets of Mental Math ask the
Page 238 and 239: 212 Secrets of Mental Math the squa
Page 240 and 241: 214 Secrets of Mental Math Why This
Page 242 and 243: 216 Secrets of Mental Math rest of
Page 246 and 247: 220 Secrets of Mental Math For date
Page 248 and 249: Chapter ∞ Epilogue: How Math Help
Page 250 and 251: 224 Secrets of Mental Math There is
Page 252 and 253: 226 Secrets of Mental Math seniors,
Page 254 and 255: 228 Secrets of Mental Math investig
Page 256 and 257: 230 Secrets of Mental Math 7. Is th
Page 259 and 260: Answers CHAPTER 1: A LITTLE GIVE AN
Page 261 and 262: Answers 235 Three-Digit Subtraction
Page 263 and 264: 13. 757 14. 259 15. 297 297 16. or
Page 265 and 266: Answers 239 2 100 5. 98 2 9600 2 2
Page 267 and 268: Answers 241 2-by-2 Addition-Method
Page 269 and 270: 2-by-2 Factoring-Method Multiplicat
Page 271 and 272: Answers 245 13. 38 63 (9 7) 15.
Page 273 and 274: Answers 247 234 17 3. 217 2 46,800
Page 275 and 276: Answers 249 CHAPTER 4: DIVIDE AND C
Page 277 and 278: Answers 251 23. 4,425,575 No: 4 4
Page 279 and 280: Answers 253 7. 7 8 1 1 4 1
Page 281 and 282: Answers 255 9. 104,972 10. 5,462,74
Page 283 and 284: Square Root Guesstimation (page 150
Page 285 and 286: 3-by-2 Exercises Using Factoring, A
Page 287 and 288: 21. 281 or 281 (280 1) 44 (11 4
Page 289 and 290: Answers 263 3. 58,324 2 “Liver”
Page 291 and 292: 3-by-3 Multiplication (page 192) 1.
Page 293 and 294: Answers 267 13. 783 (87 9) 589 1
Page 295 and 296:
Answers 269 5-by-5 Multiplication (
Page 297 and 298:
Bibliography RAPID CALCULATION Cutl
Page 299 and 300:
Index addition: an “amazing” su
Page 301 and 302:
Index 275 factoring a number: in th
Page 303 and 304:
Index 277 three-by-two problems, 16
Page 305:
About the Authors DR. ARTHUR BENJAM
show all

secrets-of-mental-math-malestrom

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?