#math trivia for #February14: 45 is the 9th triangular number: 45 = 1+2+3+…+9. How do you make a 9×9 square out of 45-unit triangles? — Burt Kaliski Jr. (@modulomathy) February 15, 2012 The nth triangular number has the form 1+2+3+…+n, and is so named because it measures the “units” in a triangularly shaped figure with … Continue reading →

#math trivia for #February13: 44 is the fifth number of the form p^2*q for distinct primes p, q. What are p and q? What were the first four? — Burt Kaliski Jr. (@modulomathy) February 13, 2012 Factoring the day’s number, 44, quickly yields the values of p and q: 44 = 2^2 * 11 , … Continue reading →

#math trivia for #February12:43 is the smallest number of form p^4+q^3 where p, q are prime. What are p and q? What’s the next number? — Burt Kaliski Jr. (@modulomathy) February 12, 2012 This is a quick one.  If 43 is the smallest number of the given form, then p, having the larger exponent, must be the smallest … Continue reading →

#math trivia for #February11:42 is the second smallest tricomposite:42 = 2*3*7; what are its eight divisors? — Burt Kaliski Jr. (@modulomathy) February 11, 2012 Tricomposite is not in the dictionary, but its definition should be clear from context:  a tricomposite number is the product of three primes.  Bicomposite numbers are common in cryptography — the … Continue reading →