F1 - Simultaneous equations $2\times 2$ $-$ Very easy

Examples :   $\left\{\begin{array}{l}2x+1=4\\ 2y-1=1\end{array}\right.$   $\left\{\begin{array}{l}x+y=1\\ x+2y=5\end{array}\right.$

F2 - Simultaneous equations $2\times 2$ $-$ Easy

Examples :   $\left\{\begin{array}{l}4x+2y=5\\ -3x+2y=-4\end{array}\right.$     $\left\{\begin{array}{l}-3y=-x+5\\ 4x=2y+4\end{array}\right.$

F3 - Simultaneous equations $2\times 2$ $-$ Like terms

Examples :   $\left\{\begin{array}{l}5y+2z-2=-3y+z+4\\ -3y+2z-2=3y+4z-3\end{array}\right.$

F4 - Simultaneous equations $2\times 2$ $-$ Decimals and fractions

Examples :   $\left\{\begin{array}{l}5.1x-2.7y=3\\ 2.9x+5y=-4\end{array}\right.$     $\left\{\begin{array}{l}\frac{2}{3}x+\frac{5}{6}y=3\\ x+4y=3\end{array}\right.$

F5 - Simultaneous equations with 2 unknowns $-$ 0, 1 or an infinity of solutions

Examples :   $\left\{\begin{array}{l}3x+2y=5\\ 9x+6y=15\end{array}\right.$   $\left\{\begin{array}{l}3x+3y=-4\\ 4x-3y=2\\ 2x+9y=-10\end{array}\right.$

F6 - Simultaneous equations $3\times 3$ $-$ Medium

Examples :   $\left\{\begin{array}{l}3x-2y-2z=2\\ y-z=1\\ 2x+3y+2z=1\end{array}\right.$     $\left\{\begin{array}{l}-x+y-z=-2\\ 2x+y+2z=-1\\ -x+2y+3z=0\end{array}\right.$