Math - Equations

Equations are mathematical expressions that contain an ‘equal to (=)’ symbol, relating two expressions.

Cheatsheet to Solve Equations

Equation Type	General Form	Solution
Addition	$x + y = n$	$x = n - y$
Subtraction	$x - y = n$	$x = n + y$
Multiplication	$x * y = n$	$x = n \div y$
Division	$x \div y = n$	$x = n * y$
Fraction	$\frac{x + y}{z} = n + m$	$x + y = z(n + m)$

Solving simple equations

To solve equations, you need to understand that both expressions are related. Whatever you do to one side, you must do to the other to maintain that relationship!

Addition Equation

$x + 4 = 9\\ x + 4 - 4 = 9 - 4\\ x = 5$

Subtraction Equation

$x - 6 = 32\\ x - 6 + 6 = 32 + 6\\ x = 38$

Multiplication Equation

$x * 8 = 32\\ x * \frac{8}{8} = \frac{32}{8}\\ x = 4$

Division Equation

$\frac{x}{8} = 6\\ 8 * \frac{x}{8} = 6 * 8\\ \cancel{8} * \frac{x}{\cancel{8}} = 48\\ x = 48$