| d0=: [: >: #: | Add 1 to cyclic countr y with upper lim x |
| d1=: +//. | Sum items of y corresponding to keys x |
| d2=: +//. {~ 'abcde'"_ i. ~.@[ | Sum y according to keys x from key set 'abcde'. (substitute your ordered keyset for 'abcde') |
| d3=: +. | Greatest common divisor of x and y |
| m4=: >:@i.@(>./) |/ ] | 1 thru max y residues of y |
| m5=: 0: = m4 | Locate positive integers <: y dividing y |
| d6=: +"1 | Add x to each row of y |
| d7=: + | Add list x to each column of table y |
| d8=: + | Add list y to each column of table x |
| d9=: *. | Least common multiple of x and y |