List the natural numbers less than 1000.
⍳1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24…
List in an interesting way the natural numbers less than 1000.
(10 * ⍳3) ∘.× ⍳10
0 1 2 3 4 5 6 7 8 9
0 10 20 30 40 50 60 70 80 90
0 100 200 300 400 500 600 700 800 900
⊖ ↓ (10 * ⍳3) ∘.× ⍳10
┌─────────────────────────────────────┬───────────────────────⋯
│0 100 200 300 400 500 600 700 800 900│0 10 20 30 40 50 60 70 ⋯
└─────────────────────────────────────┴───────────────────────⋯
A three-digit number is just a choice of one digit within each place value.
(⍳1000) ≡ , ⊃ ∘.+/ ⊖ ↓ (10 * ⍳3) ∘.× ⍳10
1