The order in which you solve the operations will provide different results and to be able to get the right answer you have to be familiar with the order of operations to know the appropiate steps to solve an operation. According to the order of operations in mathematics, exponents are given precedence over addition and multiplication. Because of that, the exponent is the first you have to solve.
3 + 2 * 3^2
3+2*9
Then, mutiplication is given precedence over addition:
3+18
Now, you can solve the addition and the result is: 21
