Chapter 1 - Introduction to Algebraic Expressions - 1.6 Subtraction of Real Numbers - 1.6 Exercise Set - Page 49: 100

$-22$

The expression $a-(-b)$ simplifies to $a+b.$ The expression $a+(-b)$ simplifies to $a-b.$ Hence, the given expression, $ 22-(-18)+7+(-42)-27 ,$ simplifies to \begin{array}{l}\require{cancel} 22-(-18)+7+(-42)-27 \\\\= 22+18+7-42-27 \\\\= 40+7-42-27 \\\\= 47-42-27 \\\\= 5-27 \\\\= -22 .\end{array}