Multiply by 39 No Calculator Shortcut

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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