Topic 2.5 · Numeracy, free at full depth on the resource hub. Two of the chapter’s four rows are reproduced below, unchanged.
Row 1 · Pitch & Period
A4 is tuned to 440 Hz; an octave up doubles frequency (440 → 880 Hz), an octave down halves it (440 → 220 Hz). Period is the flip side of frequency (T = 1/f), so a handy shortcut is worth memorising: 1 kHz ⇄ 1 ms. A 250 Hz tone’s period follows the same rule: 1/250 = 0.004 s = 4 ms.
An A note at 440 Hz is transposed one octave up. What is the new frequency?
Correct: an octave up always doubles frequency, and an octave down always halves it (440 ÷ 2 = 220 Hz).
Row 3 · Tempo in Milliseconds
Every timed effect starts from one formula: one beat in milliseconds = 60,000 ÷ BPM. At 200 BPM, that’s 60,000 ÷ 200 = 300 ms. Divide, don’t guess. From there, dotted = ×1.5 and triplet = ×⅔ of any note value, whatever the tempo.
At 200 BPM, what is the value of one beat in milliseconds, and what is a dotted version of that value?
Correct: 60,000 ÷ 200 = 300 ms, and dotted always means ×1.5 of the plain value.
Two more rows continue inside the full chapter (Decibels & Dynamic Range, and File Size) plus the worked exam anchor question that ties all four together.