Here are two fool-proof ways to easily find the major pentatonic scale-tones in any key.
Watch the introduction, then dive in.
Here's the video describing the 'scale' method of finding the major pentatonic scale-tones.
Here's the 'counting semitones' method.
Now watch the two methods being applied to find the D flat major pentatonic scale-tones.
The C, F and G pentatonic major scales use only the white piano keys.
Work through the method two-handed following the green-for left hand/orange for right hand colour coding. Say the scale-tone names (tonic, second/2, third/3, fifth/5, sixth/6) out loud every time!
C pentatonic major
F pentatonic major
G pentatonic major
When you're comfortable with these all-white-key scales, go on to Page Two of this module and work out the black-key pentatonic scales