Chapter R - Section R.1 - Basic Concepts - R.1 Exercises - Page 9: 7

$z=\{ ...,-2,-1,0,1,2,3,4 \}$

Integers are the negative, zero, and positive numbers which include $\{...,-3,-2,-1,0,1,2,3...\}$. Hence, the integers, $z$, less than or equal to $4$ are \begin{array}{l}\require{cancel} z=\{ ...,-2,-1,0,1,2,3,4 \} .\end{array}