Even though I have never needed to calculate when two trains traveling at different speeds will collide on the track in my home town, I still use Algebra every day in real life. Luckily there are GPS devices and computer programs to stop trains or switch tracks to prevent this scenario from happening.
The most common applied math calculation in real life is determining the amount of tip to give to the hair stylist, manicurist, massage therapist, bar tender, or barista or waitress. Homework problems would have students determining the amount of tip for 10%, 15%, 17%, 18%, or 20% of the bill depending on the amount of service and quality of service. Another common mental math problem is how much an item will cost if it is on the sale rack with a sign that says items are on sale for an additional 30% off of tag price. How much will that blouse cost that is tagged at $14.99 plus an additional 30% off?
Other real life problems require the student to take the dimensions of a room and to determine the area that will be covered by carpet squares or laminated flooring. Then given the amount of flooring that comes in a package, determine how many packages to purchase. Another problem will have the student determine how many gallons of paint to purchase to give the walls in the room two coats of paint. Before you purchase a swimming pool, you might want to know how many gallons of water it will take to fill the pool. Then determine how much it will cost to fill the swimming pool. If you live in an area with water use penalties, will there be extra penalties for filling the pool? Fashion designers need to determine how much fabric to buy to sew a formal dress or casual shirt and pants.
More complex homework problems will give the student an outstanding credit card balance of $12,000. Given that the interest rate charged is 22% and the minimum payment is $15 per month, how many months or years will it take to pay off the credit card balance if no new purchases are added? Balancing a check book is a homework exercise applying math to real life. Calculating the amount of federal income tax owed or refund to expect is applying math to real life. Creating a budget is applying math to real life.
Police look at skid mark distances and other measurements to determine how fast cars were going before a motor vehicle accident. Police look at bullet trajectories to determine where the sniper was hiding after a shooting fatality. Ask a law enforcement officer for some sample numbers and create applied math homework problem scenarios.
Finally, the EPA has calculations to determine how many tons of pollutants are released into the air from coal fired power plants for peak electricity demand hours. The staggering answers also help students understand the necessity for going “green” in other areas to offset the damage done to the environment from power plants.