Filed under Math Trivia …

#math trivia #167 solution

#math trivia for #June15: #167 is x*(x+2)-1 for what value of x? — Burt Kaliski Jr. (@modulomathy) June 16, 2012 This one is fairly straightforward:  If we want x*(x+2)-1 = 167, then we need x and (x+2) to be factors of 168.  Given that 168 = 12*14, it follows that x is 12. We should … Continue reading →

#math trivia #238 solution

#math trivia for #August26: #238 has the form abc where a^b = c. Which other three-digit numbers have this form? (Some may not be obvious.) — Burt Kaliski Jr. (@modulomathy) August 27, 2013 The other numbers are: 101, 111, 121, 131, 141, 151, 161, 171, 181, 191 201, 212, 224 (next would be the current 238) 301, 313, 329 401, 414 … Continue reading →

#math trivia #237 solution

#math trivia for #August25: More counting: #237 has the form abc where b^2 = a+c. How many three-digit numbers are like this? — Burt Kaliski Jr. (@modulomathy) August 26, 2013 Answer:  16.  Similar to the solution to #236, there are at least two ways to count: By a‘s, seeing how many c‘s yield a value … Continue reading →

#math trivia #236 solution

#math trivia for #August24: #236 has the form abc where a*b = c. How many three-digit numbers are like this? — Burt Kaliski Jr. (@modulomathy) August 24, 2013 The answer is 32. There are two main ways to figure it out. Assume that a is between 1 and 9 in the following, i.e., leading 0s … Continue reading →

#math trivia #235 solution

#math trivia for #August23: Four substrings of #235 are prime: 2, 3, 5, 23. Find a three-digit number where all six substrings are prime. — Burt Kaliski Jr. (@modulomathy) August 24, 2013 Let abc be a three-digit number.  If all six substrings of abc are prime, then we must have: a, b, c are prime … Continue reading →

#math trivia #234 solution

#math trivia for #August22: #234 is 33 weeks + 3 days, assuming a 7-day week. If weeks were longer, could it still be N weeks + 3 days? — Burt Kaliski Jr. (@modulomathy) August 23, 2013 The answer is yes:  234 days could still be N weeks + 3 days as long as the number … Continue reading →

#math trivia #233 solution

#math trivia for #August21: Baseball player has batting average of #233 in a typical seven-game series. How many hits did the player have? — Burt Kaliski Jr. (@modulomathy) August 22, 2013 Clearly, if the baseball player had exactly 1000 at-bats, he or she could achieve a batting average of exactly .233 with exactly 233 hits. … Continue reading →

#math trivia #232 solution

#math trivia for #August20: Fill in the blanks with operators (+ – * / ^) and digits (0-9) to complete the equation: #232 = 2_3_2_ — Burt Kaliski Jr. (@modulomathy) August 21, 2013 There are at least three answers: 232 = 2^3*29 (i.e., 8*29, where 2^3 is two cubed, or 8) 232 = 203+29 232 … Continue reading →

#math trivia #231 solution

#math trivia for #August19: #231 is the fourth day-number consisting of the digits 1, 2 and 3, and the only one with which prime factor? — Burt Kaliski Jr. (@modulomathy) August 19, 2013 There are six day-numbers consisting of the digits 1, 2, and 3, and they have the following factorizations: 123 = 3 * … Continue reading →