we start at the top and write 3 and add 4 for every line we go down: 39 * 1 = 3 39 * 2 = 7 39 * 3 = 11 39 * 4 = 15 39 * 5 = 19 39 * 6 = 23 39 * 7 = 27 39 * 8 = 31 39 * 9 = 35 39 * 10 = 39 Next, we start the bottom of the list. add on a 0 at the end, and for each line we go up, we add 1 more from the previous line 39 * 1 = 39 39 * 2 = 78 39 * 3 = 117 39 * 4 = 156 39 * 5 = 195 39 * 6 = 234 39 * 7 = 273 39 * 8 = 312 39 * 9 = 351 39 * 10 = 390
