What is \textit{substitution}?
\begin{solutionordottedlines}[2cm]
    The replacement of pronumerals or variables with numerical values in an algebraic expression.
\end{solutionordottedlines}
\begin{boxdef}
    \textbf{Pronumeral:}
    \begin{solutionordottedlines}[2cm]
         A symbol used to represent a number in algebraic expressions and equations.                            
    \end{solutionordottedlines}
\end{boxdef}
\begin{boxdef}
    \textbf{Numerical Value:}
    \begin{solutionordottedlines}[2cm]
         A specific number represented by a symbol or an expression.                                            
    \end{solutionordottedlines}
\end{boxdef}

 \begin{examplebox}                                                                                             
     \subsection{Examples}                                                                                      
     \begin{doublespace}                                                                                        
         \begin{questions}                                                                                      
             \Question[1] Evaluate $ 2x $ when $ x = 3 $                                                        
                 \begin{solutionordottedlines}[1cm]                                                             
                     $2 \times 3 = 6$                                                                           
                 \end{solutionordottedlines}                                                                    
             \Question[1] Evaluate $ 5a + 2b $ when $ a = 2 $ and $ b = -3 $                                    
                 \begin{solutionordottedlines}[1cm]                                                             
                     $5 \times 2 + 2 \times (-3) = 10 - 6 = 4$                                                  
                 \end{solutionordottedlines}                                                                    
             \Question[1] Evaluate $ 2p(3q-2) $ when $ p = 1 $ and $ q = -2 $                                   
                 \begin{solutionordottedlines}[1cm]                                                             
                     $2 \times 1 \times (3 \times (-2) - 2) = 2 \times (-6 - 2) = 2 \times (-8) = -16$          
                 \end{solutionordottedlines}                                                                    
             \Question[1] Evaluate $ 7m - 4n $ when $ m = -3 $ and $ n = -2 $                                   
                 \begin{solutionordottedlines}[1cm]                                                             
                     $7 \times (-3) - 4 \times (-2) = -21 + 8 = -13$                                            
                 \end{solutionordottedlines}                                                                    
             \Question[1] Evaluate $ a + 2b - 3c $ when $ a = 3, b = -5, c = -2 $                               
                 \begin{solutionordottedlines}[1cm]                                                             
                     $3 + 2 \times (-5) - 3 \times (-2) = 3 - 10 + 6 = -1$                                      
                 \end{solutionordottedlines}                                                                    
         \end{questions}                                                                                        
     \end{doublespace}                                                                                          
 \end{examplebox}                                                                                               

\newpage
 \begin{exercisebox}                                                                                            
     \subsection{Exercises}                                                                                     
     \begin{questions}                                                                                          
         \Question[2] Evaluate \(2x-3y\) when:                                                                  
                 \begin{parts}                                                                                  
                 \begin{multicols}{2}                                                                           
                     \part \(x = \frac{2}{5}, y = -\frac{1}{4}\)                                                
                         \begin{solutionordottedlines}[1cm]                                                     
                             $2 \times \frac{2}{5} - 3 \times \left(-\frac{1}{4}\right) = \frac{4}{5} +         
 \frac{3}{4} = \frac{16}{20} + \frac{15}{20} = \frac{31}{20} = 1\frac{11}{20}$                                  
                         \end{solutionordottedlines}                                                            
                     \part \(x = \frac{1}{3}, y = \frac{1}{6}\)                                                 
                         \begin{solutionordottedlines}[1cm]                                                     
                             $2 \times \frac{1}{3} - 3 \times \frac{1}{6} = \frac{2}{3} - \frac{3}{6} =         
 \frac{2}{3} - \frac{1}{2} = \frac{4}{6} - \frac{3}{6} = \frac{1}{6}$                                           
                         \end{solutionordottedlines}                                                            
                 \end{multicols}                                                                                
                 \end{parts}                                                                                    
         \Question[2] Evaluate \(p^2 -2q\) when:                                                                
             \begin{parts}                                                                                      
                 \begin{multicols}{2}                                                                           
                 \part \(p=-7, q = 2\)                                                                          
                         \begin{solutionordottedlines}[1cm]                                                     
                             $(-7)^2 - 2 \times 2 = 49 - 4 = 45$                                                
                         \end{solutionordottedlines}                                                            
                 \part \(p = -\frac{1}{3}, q = \frac{5}{6}\)                                                    
                         \begin{solutionordottedlines}[1cm]                                                     
                             $\left(-\frac{1}{3}\right)^2 - 2 \times \frac{5}{6} = \frac{1}{9} - \frac{10}{6} = 
 \frac{1}{9} - \frac{15}{9} = -\frac{14}{9} = -1\frac{5}{9}$                                                    
                         \end{solutionordottedlines}                                                            
                 \end{multicols}                                                                                
             \end{parts}                                                                                        
     \end{questions}                                                                                            
 \end{exercisebox}