From Bach’s fugues to Britney’s choruses, Sarah Hart shows how maths shapes the music that shapes our lives.What makes music work? Why do rhythms move us and melodies stay with us for life? In 5, 6, 7, 8!, mathematician and bestselling author Sarah Hart unlocks the fascinating connections between music and mathematics.From the hidden arithmetic in Pink Floyd’s ‘Money’ to the melodic structures behind Britney Spears' ‘Hit Me Baby One More Time’, Hart reveals how deep mathematical patterns underpin the tunes we hum, dance to and adore. Blending lively storytelling with playful analysis, she takes us through seven iconic songs – one for each note of the musical scale – showing how rhythm, harmony and melody have roots in math across cultures and centuries.Perfect for music lovers, math geeks, and anyone curious about the world’s most universal language, 5, 6, 7, 8! is a smart, surprising and joyful read.