#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 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 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 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 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 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 →