Another solution with TikZ chains

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{chains}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[spanish]{babel}
\usepackage{lmodern}
\begin{document}
\begin{enumerate}
\item
\begin{tikzpicture}[start chain,
every node/.style={on chain},
bloc/.style={fill=red!80!blue!70,
minimum width=3.5cm, minimum height=1.2cm,
text=white, font=\sffamily, align=center,
outer sep=0pt},
simbol/.style={text=blue!80,
font=\bfseries\Large, outer sep=0pt},
node distance=0pt,
]
\node[bloc] {Gasto en\\ pensiones};
\node[simbol] {=};
\node[bloc, fill=green!80!black] {Ingresos del sistema de \\ pensiones};
\end{tikzpicture}
\item
\begin{tikzpicture}[start chain,
every node/.style={on chain},
bloc/.style={fill=red!80!blue!70,
minimum width=1.8cm, minimum height=1.5cm,
text=white, font=\sffamily, align=center,
outer sep=0pt},
simbol/.style={text=blue!80,
font=\bfseries\Large, outer sep=0pt},
node distance = 0pt
]
\node[bloc] {IRP};
\node[simbol] {+};
\node[bloc] {Crecimiento\\ número de \\ pensiones};
\node[simbol] {+};
\node[bloc] {Efecto\\ sustitución\\ (altas/bajas)};
\node[simbol] {=};
\node[bloc, fill=green!80!black] {Inflación};
\node[simbol] {+};
\node[bloc, fill=green!80!black] {Crecimiento\\ real de los\\ ingresos};
\end{tikzpicture}
\item
\begin{tikzpicture}[start chain,
every node/.style={on chain},
bloc/.style={fill=red!80!blue!70,
minimum width=1.7cm, minimum height=1.5cm,
text=white, font=\sffamily, align=center,
outer sep=0pt},
simbol/.style={text=blue!80,
font=\bfseries\Large, outer sep=0pt,
minimum height=1.5cm},
node distance = 0pt
]
\node[bloc] {IRP};
\node[simbol] {=};
\node[bloc, fill=blue!30] {Inflación};
\node[simbol] {+};
\node[bloc, fill=blue!30] {Crecimiento\\ real de los\\ ingresos};
\node[simbol, fill=blue!30] {-};
\node[bloc, fill=blue!30] {Crecimiento\\ número de \\ pensiones};
\node[simbol, fill=blue!30] {-};
\node[bloc, fill=blue!30] {Efecto\\ sustitución\\ (altas/bajas)};
\end{tikzpicture}
\item
\begin{tikzpicture}[start chain,
bloc/.style={fill=red!80!blue!70,
minimum width=2.2cm, minimum height=1.5cm,
text=white, font=\sffamily, align=center,
outer sep=0pt},
simbol/.style={text=blue!80,
font=\bfseries\Large, outer sep=0pt},
lbl/.style={text=white, font=\sffamily,
align=center, outer sep=1mm,
minimum width=2.2cm, fill=red!80!blue!70},
node distance = 0pt
]
\node[on chain, bloc,
label={[lbl]below:1,5\%}] {IRP};
\node[on chain, simbol] {=};
\node[on chain, bloc, fill=green!80!black,
label={[lbl,fill=green!80!black]below:1,5\%}] {Inflación};
\node[on chain, simbol] {+};
\node[on chain, bloc, fill=green!80!black,
label={[lbl,fill=green!80!black]below:2,0\%}] {Crecimiento\\ real de los\\ ingresos};
\node[on chain, simbol] {-};
\node[on chain, bloc,
label={[lbl]below:1,2\%}] {Crecimiento\\ número de \\ pensiones};
\node[on chain, simbol] {-};
\node[on chain, bloc,
label={[lbl]below:0,8\%}] {Efecto\\ sustitución\\ (altas/bajas)};
\end{tikzpicture}
\end{enumerate}
\end{document}