What does equation mean?

Answer 1

An equation is an expression or statement of equivalence or "sameness" between two (or more) things. It might be as simple as a conversion factor like this:

36 inches = 3 feet = 1 yard

Or it could be some simple expressions using numbers thus:

5 + 7 = 12, or 1/2 + 1/3 = 5/6

Perhaps it is an expression such as this electrical formula:

P = I x E

where P = power in watts, I = current in amperes or amps, and E = voltage in volts. (It tells us that if we have 1 volt driving 1 amp of current through a component, we have 1 watt of power developed in that component.)

We could move on to a bit more complex algebraic expression:

ax2 + bx + c = 0

An equation tells us that all of that which is on one side is equal to or the same as all that which is on the other side. It is a mathematical expression of that equivalence.