Prealgebra (7th Edition)

a)$4+4+4+4+4$ b)$4\cdot 5 = 4+4+4+4+4 = 5+5+5+5$
a)Repeated addition is multiplication. $4 \cdot 5$ means adding $4$ five times. b)$4\cdot 5 = 5\cdot 4$ so $4\cdot 5$ can also be written as $5+5+5+5$