How do you use the order of operations to simplify expressions with exponents

It could be PEMDAS.
That means solve by this order:
1). Parenthesis
2). Exponents
3). Multiplication
4). Division
5). Addition
6). Subtraction

To remember the order they say it like
this " Please Excuse My Dear Aunt Sally "

Total number of T-shirts= 200

Cost per T-shirt (without shipping ) = $2.80

Shipping cost per t-shirt ; 5% of a T-shirt = 0.05 *2.80 = $0.14

Total cost of T-shirt (shipping included) = 2.80 +0.14 = $2.94

Markup = 150% of total cost = 1.50 * 2.94 = $4.41

To get the price at which Michelle will sell each T-shirt , add total cost  to the markup; 2.94 +4.41 = 7.35.

Therefore, selling price will be $7.35