The numbers 12 and 9 share the common factors 1 and 3. Then do multiplies and divides from left to right. The order of operations From left to right start with division and multiplication and continue with addition and subtraction.
The oder of operations is PEMDAS which stands for.
Dont forget if a calculation has division and multiplication in it. The order in which operations should be done is abbreviated as PEMDAS. It is the set of rules that determines which operations should be done before or after others. Or go from right to left.