The Major Scale and Scale Degrees
How the major scale is built from whole and half steps, and the name/number of each degree.
The major scale is built from a fixed pattern of whole (W) and half (H) steps starting on any note: W-W-H-W-W-W-H. Starting on C, that gives you C-D-E-F-G-A-B-C — the "white keys" scale, with the half steps falling exactly between E-F and B-C.
Each note of the scale is a scale degree, numbered 1 through 7 (a "step" — ступень). Three degrees are the pillars of the key: the 1st degree is the Tonic (тоника) — the note the scale is named after and the point of rest; the 4th degree is the Subdominant (субдоминанта); the 5th degree is the Dominant (доминанта). The 7th degree, a half step below the tonic, is the Leading Tone (вводный тон) — it pulls strongly back to the tonic.
The remaining degrees (2, 3, 6) are simply called by their number in Russian pedagogy ("вторая ступень", "третья ступень"...), while Western theory gives them names too: Supertonic, Mediant, Submediant.
In the exercise below, the tonic is highlighted in orange and a second note lights up in green — name its scale degree.