To evaluate this expression, we use PEMDAS.

We add and subtract, from left to right:

\begin{align*} 2 + 5.2 - 3 &= \\[5pt] \left(2 + 5.2\right) - 3 &= \\[5pt] 7.2 - 3 &= \\[5pt] 4.2 \end{align*}

To evaluate this expression, we use PEMDAS.

We subtract twice, from left to right:

\begin{align*} 3 - \dfrac 5 4 - 1 &= \\[5pt] \left(3 - \dfrac 5 4\right) - 1 &= \\[5pt] \left(\dfrac{12}{4} - \dfrac 5 4\right) - 1 &= \\[5pt] \dfrac{12-5}{4} - 1 &= \\[5pt] \dfrac{7}{4} - 1 &= \\[5pt] \dfrac 7 4 - \dfrac 4 4 &=\\[5pt] \dfrac{7-4}{4} &=\\[5pt] \dfrac 3 4 \end{align*}

To evaluate this expression, we use PEMDAS.

We add and subtract, from left to right:

\begin{align*} \dfrac 3 4 + 2 - \dfrac 3 2 &= \\[5pt] \left(\dfrac 3 4 + 2\right) - \dfrac 3 2 &= \\[5pt] \left(\dfrac{3}{4} + \dfrac 8 4\right) - \dfrac 3 2 &= \\[5pt] \dfrac{3+8}{4} - \dfrac 3 2 &= \\[5pt] \dfrac{11}{4} - \dfrac 3 2 &= \\[5pt] \dfrac{11}{4} - \dfrac 6 4 &=\\[5pt] \dfrac{11-6}{4} &=\\[5pt] \dfrac 5 4 \end{align*}

To evaluate this expression, we use PEMDAS.

We multiply and divide, from left to right:

\begin{align*} \dfrac 1 2 \times 6 \div 5 &= \\[5pt] \left(\dfrac 1 2 \times 6\right) \div 5 &= \\[5pt] \left(\dfrac 1 2 \times \dfrac 6 1\right) \div 5 &= \\[5pt] \dfrac{1\times 6}{2\times 1} \div 5 &= \\[3pt] \dfrac 6 2 \div 5 &= \\[5pt] 3 \div 5 &= \\[3pt] 0.6 \end{align*}

To evaluate this expression, we use PEMDAS.

We divide and multiply, from left to right:

\begin{align*} \require{cancel} 3\div 6 \times 2 &= \\[3pt] (3\div 6) \times 2 &= \\[3pt] \dfrac 3 6 \times 2 &= \\[5pt] \dfrac{3}{6} \times \dfrac 2 1 &= \\[5pt] \dfrac{3\times 2}{6\times 1} &= \\[5pt] \dfrac 6 6 &= \\[3pt] 1 \end{align*}

To evaluate this expression, we use PEMDAS.

We multiply and divide, from left to right:

\begin{align*} \require{cancel} 5\times \left(-\dfrac 3 2\right) \div 9 &= \\[5pt] \left(5 \times \left(-\dfrac 3 2\right)\right) \div 9 &= \\[5pt] \left(\dfrac 5 1 \times \left(-\dfrac 3 2\right)\right) \div 9 &= \\[5pt] \left(\dfrac{5 \times (-3)}{1\times 2}\right) \div 9 &= \\[5pt] \left(-\dfrac{15}{2}\right) \div 9 &= \\[5pt] \left(-\dfrac{15}{2}\right) \times \dfrac 1 9 &= \\[5pt] -\dfrac{15\times 1}{2\times 9} &= \\[5pt] -\dfrac{15}{18} &= \\[5pt] -\dfrac{5}{6} \end{align*}

To evaluate this expression, we use PEMDAS.

First, we multiply:

\begin{align*} \dfrac 1 4 \times 8 - 3.1 &= \\[5pt] \left(\dfrac 1 4 \times 8\right) - 3.1 &= \\[5pt] \left(\dfrac 1 4 \times \dfrac 8 1\right) - 3.1 &= \\[5pt] \dfrac{1\times 8}{4\times 1} - 3.1 &= \\[5pt] \dfrac 8 4 - 3.1 &= \\[5pt] 2-3.1 \end{align*}

Finally, we subtract:

\begin{align*} 2 - 3.1 &= -1.1 \end{align*}

To evaluate this expression, we use PEMDAS.

First, we divide:

\begin{align*} \require{cancel} (-3) \div \dfrac 3 5 + 2 &= \\[5pt] \left((-3) \div \dfrac 3 5\right) + 2 &= \\[5pt] \left((-3) \times \dfrac 5 3\right) + 2 &= \\[5pt] \left(-\dfrac 3 1\times \dfrac 5 3\right) + 2 &= \\[5pt] -\dfrac{3\times 5}{1\times 3} + 2 &= \\[5pt] -\dfrac{\cancel 3\times 5}{1\times \cancel 3} + 2 &= \\[5pt] -5+2 \end{align*}

Finally, we add:

\begin{align*} -5 + 2 &= -3 \end{align*}

To evaluate this expression, we use PEMDAS.

First, we multiply:

\begin{align*} 1.5 - 3 \times (-2) &= \\[3pt] 1.5 - \left(3 \times (-2) \right) &= \\[3pt] 1.5 - (-6) \end{align*}

Finally, we subtract:

\begin{align*} 1.5 - (-6) &= \\[3pt] 1.5 + 6 &= \\[3pt] 7.5 \end{align*}

To evaluate this expression, we use PEMDAS.

First, we perform the operation inside the parentheses:

\begin{align*} \left( 10 - 5 \right) \times \dfrac{1}{2} &= \\[5pt] 5 \times \dfrac{1}{2} \end{align*}

Finally, we multiply:

\begin{align*} 5 \times \dfrac{1}{2} &= \\[5pt] \dfrac{5}{1} \times \dfrac{1}{2} &= \\[5pt] \dfrac{5\times 1}{1\times 2} &= \\[5pt] \dfrac 5 2 \end{align*}

To evaluate this expression, we use PEMDAS.

First, we perform the operation inside the parentheses:

\begin{align*} (-3) \times (0.6-0.3) &= \\[3pt] (-3) \times 0.3 \end{align*}

Finally, we multiply:

\begin{align*} (-3) \times 0.3 &= -0.9 \end{align*}

To evaluate this expression, we use PEMDAS.

First, we perform the operation inside the parentheses:

\begin{align*} (-9+10)\div \left( 7 - 3 \right) &= \\[5pt] 1 \div 4 \end{align*}

Finally, we divide:

\begin{align*} 1 \div 4 &= 0.25 \end{align*}