Algebra
- In algebra, we use addition, subtraction, multiplication, division, and exponents to find the values of variables in an equation.
- For example, let's say we want to find x in this equation: x - 5 = 2
- If we use algebra, we could add five to both sides (x - 5 + 5 = 2 + 5, x = 7) to find out that x equals 7.
- Since the rules of algebra work in real life and we can use numbers to represent the values of real things, we can use algebra to solve real problems.
- For example, if I give 5 coins to a friend and have 10 left over, how many did I have before? We are trying to find out how many I had before, so we will call that x. How many coins I had before minus how many I gave to my friend equals how many coins I have now, so x - 5 = 10. We can add five to each side to find that x - 5 + 5= 10 + 5, x = 15. X, the number I had before, equals 15. I had 15 before.