In the beginning of J TECH Grade 3, I am summarizing the facts that students should have learned in Grade 2 at the outset.
Addition and Subtraction are a pair of inverse functions. Students learned addition facts for numbers 0 to 10. The sums range from 0 to 20. Thus the inverse must include the numbers from 0 - 20 divided by 1 to 10. You can't divide by 0. Students haven't met negative numbers. So here's the charts I want. Do you know any ways I could do this more simply or elegantly? A=:":((i.20)>:/i.10)*(i.20)-/i.10 B=:(|._3*i.10),10$0 C=:B|.!.' '"0 1 A D=:(-B)|.!.' '"0 1 C TOP=: (<' - '),<}.,' ' ,"1":,.>:i.10 BOT=:(<,.>:i.20),<D ]PLUS=:+table i.11 ---T--------------------------------┐ │+ │ 0 1 2 3 4 5 6 7 8 9 10│ +--+--------------------------------+ │ 0│ 0 1 2 3 4 5 6 7 8 9 10│ │ 1│ 1 2 3 4 5 6 7 8 9 10 11│ │ 2│ 2 3 4 5 6 7 8 9 10 11 12│ │ 3│ 3 4 5 6 7 8 9 10 11 12 13│ │ 4│ 4 5 6 7 8 9 10 11 12 13 14│ │ 5│ 5 6 7 8 9 10 11 12 13 14 15│ │ 6│ 6 7 8 9 10 11 12 13 14 15 16│ │ 7│ 7 8 9 10 11 12 13 14 15 16 17│ │ 8│ 8 9 10 11 12 13 14 15 16 17 18│ │ 9│ 9 10 11 12 13 14 15 16 17 18 19│ │10│10 11 12 13 14 15 16 17 18 19 20│ L--+--------------------------------- ]MINUS=:TOP,:BOT ----T-----------------------------┐ │ - │ 1 2 3 4 5 6 7 8 9 10│ +---+-----------------------------+ │ 1 │ 0 │ │ 2 │ 1 0 │ │ 3 │ 2 1 0 │ │ 4 │ 3 2 1 0 │ │ 5 │ 4 3 2 1 0 │ │ 6 │ 5 4 3 2 1 0 │ │ 7 │ 6 5 4 3 2 1 0 │ │ 8 │ 7 6 5 4 3 2 1 0 │ │ 9 │ 8 7 6 5 4 3 2 1 0 │ │10 │ 9 8 7 6 5 4 3 2 1 0│ │11 │10 9 8 7 6 5 4 3 2 1│ │12 │11 10 9 8 7 6 5 4 3 2│ │13 │12 11 10 9 8 7 6 5 4 3│ │14 │13 12 11 10 9 8 7 6 5 4│ │15 │14 13 12 11 10 9 8 7 6 5│ │16 │15 14 13 12 11 10 9 8 7 6│ │17 │16 15 14 13 12 11 10 9 8 7│ │18 │17 16 15 14 13 12 11 10 9 8│ │19 │18 17 16 15 14 13 12 11 10 9│ │20 │19 18 17 16 15 14 13 12 11 10│ L---+------------------------------ Thanks in advance. Linda ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
