Always use BODMAS (also known as BIDMAS or PEMDAS):
Brackets
Of (or other operations like powers/roots)
Divide
Multiply
Add
Subtract
Examples
\[
12 \div 3 \times 4
\]
\[
= 4 \times 4
\]
\[
= 16
\]
\[
7 + (6 \times 5)
\]
\[
= 7 + 30
\]
\[
= 37
\]
\[
20 - 12 \div 3
\]
\[
= 20 - 4
\]
\[
= 16
\]
\[
(18 - 6) \div 3
\]
\[
= 12 \div 3
\]
\[
= 4
\]
\[
4 + 6 \times (3 + 2)
\]
\[
= 4 + 6 \times 5
\]
\[
= 4 + 30
\]
\[
= 34
\]
\[
30 \div (2 \times 3)
\]
\[
= 30 \div 6
\]
\[
= 5
\]
\[
(8 + 4) \div 2 + 6
\]
\[
= 12 \div 2 + 6
\]
\[
= 6 + 6
\]
\[
= 12
\]