Equations seem totally absurd to students, but they are used in a variety of everyday tasks. An example of equations use by professionals is in the field of finance. Arbitrage pricing, interest rates, inflation and elasticity (of demand or supply) are calculated with the use of certain equations. In addition, linear equations can also help consumers make the best decision when choosing a service charging by the minute (such as telecommunications companies' rates).
Basic money-management skills are usually learned in elementary school. Money management is also one of the most widely applied algebra skills we use. An example of a problem requiring you to use algebra is "How much do you spend each month when you take two bus rides, each costing $1.35, every weekday?" People need to do this type of math on a regular basis to make financial decisions.
Algebra in school tasks is based on the four basic operations: addition, subtraction, multiplication and division. For example, "how much of your $20 should you give to each of your four children?" or "a car using 0.25 gallons of gas per mile starts with 30 gallons; how much gas is left after 4 miles?" These objectives sound exactly like problems an adult faces everyday, trying to make do with limited resources.
When you are a student, you may be asked to calculate 4 percent of 200. When you grow up, you may try to calculate 4 percent because it's your loan interest. As percentages are used widely in everyday life (for example "40 percent off cleaning products" or a "2 percent raise in sales tax"), you can benefit from knowledge of percentages.