A combination of 10 Heavenly Stems and 12 Earthly Branches, the year’s symbol creates a sequence of year names that eventually repeat. Students explore the least common multiple of these two cycles without ever hearing the term LCM.
Most of the life cycle of the Magicicada Septendecim is spent underground. Then at 17 year intervals, these cicadas emerge from the ground, climb deciduous trees, molt into adults, mate, lay eggs, and die. Why does the 17 year interval…