Need step by step explanations on how to do it

Instructions The two real-life scenarios below represent the importance of organization in mathematics. Specifically, the importance of being able to find a percentage of an amount without a calculator. In each scenario box below, add your explanations in the spaces provided. Scenario 1 You are in a store and want to ensure you have enough cash for an unplanned purchase. You need to be able to calculate the sales tax for your purchase without a calculator. Part A: Identify a situation that would fit into this scenario and explain how you would organize this calculation to solve it without a calculator. Assume a 5% sales tax rate. For full credit you will need the cost of the item, an explanation of how you would calculate the sales tax, and the total cost