Mathematical Puzzles : What is -LRB- -RRB- + -LRB- -RRB- + -LRB- -RRB- = 30 using 1,3,5,7,9,11,13,15 ?
Why does the matrix -LSB- math -RSB- M = \ begin -LCB- bmatrix -RCB- 1 & 2 & 3 \ \ 4 & 5 & 6 \ \ 7 & 8 & 9 \ end -LCB- bmatrix -RCB- -LSB- / math -RSB- have a -LSB- math -RSB- 0 -LSB- / math -RSB- determinant ?