K. 411. The power x5 cannot only be calculated by doing the multiplication x.x.x.x.x, but also with fewer multiplications, by calculating partial results (e.g. y=x.x) and obtaining the final answer by multiplying those: y.y.x, which only makes three multiplications altogether. Express the power x23 with less than 10 multiplications to carry out.
This problem is for grade 9 students only.
Deadline expired on 10 March 2014.
Google Translation (Sorry, the solution is published in Hungarian only.)
Megoldás. Egy lehetséges út 7 szorzással: x.x=x2, x2.x2=x4, x4.x4=x8, x8.x8=x16, x16.x4.x2.x=x23.
Egy lehetséges út 6 szorzással: x.x=x2, x2.x=x3, x2.x3=x5, x5.x5=x10, x10.x3=x13, x10.x13=x23.