A letter used to represent an unknown number.
Variable
Solve for x:
x + 5 = 10
x = 5?
What is the first step to solve:
2x + 1 = 5?
Subtract 1 from both sides
What equation matches: "You have 3 cats. You adopt x more. Now you have 5 cats.
3 + x = 5
A mathematical sentence that contains an equal sign.
Equation
Solve for y:
y - 2 = 8
y = 10
Solve for x:
2x + 1 = 5
x = 2
What equation matches: "4 identical toys cost $12 total. What is the price (p) of one?"
4p = 12
The number that is multiplied by the variable (e.g., the 4 in 4y).
coefficient
Solve for m:
3m = 15
m = 5
What is the first step to solve:
4y - 2 = 10?
add 2 to both sides
Solve: You had some money (m). You spent $2. Now you have $8. How much did you start with?
$10
Doing the opposite action to solve an equation (like subtracting when you see addition).
inverse operation
Solve for k:
k / 2 = 6
k = 12
Solve for y:
4y - 2 = 10
y = 3
Solve: You earn $2 per chore, plus a $5 bonus. You made $11 total. How many chores did you do?
3 chores
A plain number that sits all by itself in an equation, with no variable attached
constant
Solve for p:
10 + p = 25
p = 15
Solve for w:
5w + 10 = 20
w = 2
Solve: A notebook costs $3. You buy some (b) and pay a $2 tax. The total is $14. How many notebooks did you buy?
4 notebooks