Vocabulary
Addition
Subtraction
Division
Multiplication
100

What is a variable?

 A letter or symbol that stands for a number we don't know yet.

100

17+k=31

14

100

x - 4 = 10

14

100

x ÷ 4 = 3

12


100

3x = 12

4

200

What is a constant?

A number that always stays the same.

200

r+19=72
 

53

200

x - 3 = 7
 

10

200

x ÷ 2 = 5

10

200

4x = 20

5

300

 An operation that does the opposite of another

Inverse operation

300

x + 3 = 9

6

300

x - 9 = 20

29

300

x ÷ 5 = 9

45

300

5x = 25

5

400

To get the variable all by itself on one side of the equation is called what?

isolate

400

x + 25 = 140
 

115

400

x - 15 = 12
 

27

400

: x ÷ 8 = 6

48

400

7x =63

9
500

 A number that is multiplied by a variable is called what?
 

coefficient

500

213+y=361
 

148

500

x - 50 = 1257

1307

500

x ÷ 12 = 11

132

500

12x=108

9