#### Answer

False

#### Work Step by Step

Converting the expression $5\times5\times5\times a\times b\times b$ to exponential notation, we must count the number of times each number is being multiplied by itself and make that the exponent for the number being multiplied. Since $5$ is multiplied by itself three times, $a$ is multiplied by itself once, and $b$ is multiplied by itself twice, the expression in exponential form should read $5^3ab^2$, not $5^3ab$.