Scales: Natural Minor — Minor Pentatonic — Blues Theory Things   William Wieland
The minor pentatonic scale is 1 3 4 5 7 (8) of a natural minor scale.
The minor pentatonic scale is 6 1 2 3 5 (6) of a major scale.
Do-based minor:   do me fa sol te (do)
La-based minor:   la do re mi sol (la)
The blues scale simply adds a raised 4 to the minor pentatonic scale.
The blues scale is 1, 4, 5, and blue notes: lowered 3, lowered 5 and lowered 7. (Think odd numbers.)
A natural minor scale
  A minor pentatonic scale
  A blues scale (guitars)
E natural minor scale
  E minor pentatonic scale
  E blues scale (guitars)

F natural minor scale
  F minor pentatonic scale
  F blues scale (horns)
B flat natural minor scale
  B flat minor pentatonic scale
  B flat blues scale (horns)

The black keys on the piano are an E flat minor pentatonic scale (or D sharp). Add an A natural for a blues scale.